Chemistry topics, Sodium, Na

School Science Lessons
2024-12-26

Sodium, Na
Silver
Strontium
Please send comments to: j.elfick@uq.edu.au
Contents
Sodium Table of the Elements
Sodium properties
Sodium compounds
Sodium reactions
Sodium toxicity
Prepare sodium compounds (List)
Reactions of sodium with water
Solution recipes
Tests for sodium bicarbonate in a stomach powder: 12.1.20
Tests for sodium chloride, flame test: 12.1.29

Sodium reactions
Acids with sodium bicarbonate: 12.1.18
Acids with sodium carbonate: 12.1.25
Acids with sodium thiosulfate: 12.1.40
Buffer solutions: 12.1.7
Group 6 tests, Na+: 12.11.3.27
Heat sodium bicarbonate: 12.1.17
Heat sodium carbonate crystals: 12.1.24
Heat sodium thiosulfate crystals: 12.1.39
Prepare soda lime: 34.2.12
Reactions of chlorine with sodium: 12.4.7
Reactions of sodium with water: 12.1.30
Sodium bicarbonate precipitates: 12.1.19
Sodium bicarbonate prevents milk from going sour: 12.1.21
Sodium carbonate efflorescence: 12.1.23
Sodium carbonate precipitates: 12.1.26
Sodium chloride flame tests: 12.1.29
Sodium hypochlorite, use in swimming pools: 12.1.11
Sodium hypochlorite: 12.1.49
Sodium hypochlorite bleach: 12.1.10
Sodium thiosulfate decomposes to form sodium sulfate and sodium pentasulfide: 12.1.46
Sodium thiosulfate with dilute hydrochloric acid forms sulfur dioxide and sulfur: 12.1.47
Sodium thiosulfate with iodine forms sodium tetrathionate and sodium iodide: 12.1.45
Sodium thiosulfate with silver chloride or silver bromide: 12.1.48
Soft drinks, carbonated beverages, fizzy drinks, sports drinks: 15.8.6
Storing sodium and potassium: 3.7.9
Tests for sodium: 12.11.3.27

Sodium properties
Sodium, Na, metal (natrium), pellets (in liquid paraffin), cube, AAS solution, toxic if ingested, harmful, Corrosive, FLAM, COR 1428
Sodium, Na (Latin, Sodanum barilla, plant burned to extract sodium), is a silver-white, alkali metal, is very reactive in sea water with sodium chloride.
Sodium, is a soft metal, which readily tarnishes in air. .
Direct union of the elements occurs, sodium and chlorine.
Sodium, Na (in liquid paraffin) (natrium), is a very reactive, soft and shiny alkali metal with a silvery colour, 2.5% of the earth's crust in many different minerals.
It does not occur in the free state and soon becomes dull in air.
It is available as sodium metal in liquid paraffin, extracted by electrolysis of fused sodium hydroxide, rock salt (halite) and evaporated sea water.
It is used in sodium vapour discharge lamps.
Sodium reacts with dilute hydrochloric acid or sulfuric acid to form hydrogen and metal ion.
Sodium reacts with concentrated oxidizing acids, nitric acid or sulfuric acid to produce high oxidation number ions, and sulfur dioxide or nitrogen dioxide.
Sodium reacts with cold water and reacts with air to form peroxides.
Sodium has greater concentration in extra cellular fluids than in intracellular fluids.
The level of sodium ion in blood is 310 to 333 mg per 100 mL of serum.
Sodium metal reacts violently with water to form highly corrosive sodium hydroxide and hydrogen gas.
The surface of the reacting sodium may become sufficiently hot to ignite the hydrogen and explode the air / hydrogen mixture.
Sodiu reacts explosively with acids, bromides, iodine, sulfur, polyhalogenated hydrocarbons, e.g. chloroform.
The surface of sodium metal is coated with a mixture of the oxide and hydroxide, both of which hygroscopic.
This causes the surface of sodium metal to absorb moisture from the air, resulting in further reaction to form hydrogen and sodium hydroxide.
Sodium metal, unprotected in a container, may absorb sufficient moisture to form an air / hydrogen mixture and then becomes hot enough to ignite the mixture.
The ignition may cause an explosion, so store sodium under paraffin oil or kerosene.
Store sodium on a low shelf to reduce the chance of dropping the container.
Cut sodium on a clean dry surface with a clean dry blade, e.g. an all metal scalpel or small knife, not a scalpel with detachable blade.
Do not lose small pieces of cut sodium.
Dispose of sodium waste by reacting it with ethanol or methylated spirit in a beaker in a fume cupboard.
The reaction of sodium with an alcohol is less violent than with water, so it is relatively slow and easy to control, but there is still a risk of fire.
The use of flammable solvents near sodium is always a risk.
Atomic number: 11, Relative atomic mass: 22.9898, RD 0.97, MP = 97.8 oC, b.p. = 890 oC
Specific heat capacity: 1.23 × 103 J kg-1 K-1

Sodium compounds
Albite, sodium feldspar, Na2O3.Al203.2Si02, (Geology)
Borax: | Na2B4O7.10H2O | Na2[B4O5(OH)4].8H2O | 35.13.3.1, (Geology)
Borosilicate glass, Pyrex: 7.9.10
Calcined soda, anhydrous sodium carbonate
Cryolite, Na3.AlF6, (repeating unit) sodium aluminium fluoride: 35.20.13, (Geology)
Disodium 5'-ribonucleotides, E635, (flavouring) (in packets of potato chips, instant noodles, pies)
E635, flavour enhancerm from combining sodium salts of the natural compound guanylic acid (E626) and inosinic acid (E630)
EDTA | C10H12O8CaN2Na2·2H2O | C10H16N2O8 | (HOOCCH2)2NCH2)2 | 4.0
Glass transition temperature (Tg): 3.4.1
Halite, NaCl, sodium chloride, rock salt: 35.20.19, (Geology)
Heat sodium carbonate crystals: 12.1.24
Nahcolite, NaHCO3, thermokalite, sodium hydrogen carbonate mineral, in evaporates
Natron, sodium carbonate decahydrate
Soda alum, NaAl(SO4)2·12H2O, sodium aluminium sulfate
Soda ash
Soda cellulose
Soda lime
Sodamide, NaNH2, sodium amide
Sodium acetate (sodium ethanoate)
Sodium adipate, E356, C6H8Na2O4, (acidity regulator, firming agent)
Sodium alginate, C6H7NaO6)n or C6H9NaO7, E401 (from brown algae, vegetable gum, emulsifier and increase viscosity, [texture] of food
Sodium alginate, algin, harmful in excess, sold as "Instant Worms"!
Sodium aluminate, NaAlO2, harmful to mucous membranes if inhaled
Sodium aluminium fluoride, Na3AlF6: 35.20.13, (Geology)
Sodium aluminium phosphate, E541 (emulsifier, acidity regulator), (from alumina + phosphoric acid + sodium hydroxide)
Sodium aluminium phosphate, NaH14Al3(PO4)8.4H2O, E541, phosphate aerator in some baking powders
Sodium aluminium silicate, 14SiO2Al2O3Na2O3H2O, Na2Al2Si14O32·3H2O, (sodium aluminosilicate)
Sodium aluminium silicate, E554 (anti-caking agent) (in table salt, dried milk, flour)
Sodium aluminium sulfate, NaAl(SO4)2.12H2O, soda alum
Sodium amalgam
Sodium amide, NaNH2, sodamide, toxic if ingested, reacts violently with water, Not permitted in schools
Sodium arsenate, All called "sodium arsenate": | NaH2AsO4.H2O | Na2HAsO4 | Na3AsO4 | (colourless salts, highly toxic!)
Sodium arsenate heptahydrate, sodium arsenate, dibasic, 7-hydrate, Na2HAsO4.7H2O, or AsH15Na2O11, highly toxic! (ant baits)
Sodium arsenite, Na3As, Arboricides: 4.2
Sodium ascorbate, Sodium L-ascorbate, C6H7NaO6, E301, (sodium salt of vitamin C), (antioxidant)
Sodium azide, NaN3, insoluble metal salts explosive, toxic, Environment danger, Not permitted in schools, Sodium benzoate
Sodium bicarbonate
Sodium bismuthate, NaBiO3, harmful if ingested
Sodium bitartrate monohydrate, C4H5NaO6.H2O, tartaric acid monosodium salt, E335, food additive, acidity regulator
Sodium borohydride, NaBH4, harmful if ingested, skin irritant
Sodium borohydride with water slowly forms hydrogen gas that may explode when mixed with air and ignited
Sodium bromide, NaBr, harmful if ingested, may be substituted for potassium bromide
Sodium bromide, Low cost: from swimming pool supply stores as sodium bromide, “bromine base”
Sodium bromide is used to raise the bromine levels in a swimming pool before using bromine tablets
Sodium butyrate, CH3.CH2.CH2COONa, butyric acid sodium salt
Sodium carbonate Soda ash, washing soda
Sodium carboxy methylcellulose, food additive E468, carrier
Sodium chlorate, NaClO3
Sodium chloride, NaCl
Sodium chlorite, NaClO2
Sodium chromate, Na2CrO4.4H2O, For 0.1 M solution, 23.4g in 1 L water, highly toxic if ingested, carcinogenic, skin irritant
Sodium chromate, Solution < 1%, Not hazardous
Sodium citrate
Sodium cobaltinitrite
Sodium cyanide, NaCN, cyanogran, Extremely toxic by all routes, with acids forms cyanide gas
Sodium dichlor, sodium dichloroisocyanurate, C3Cl2N3NaO3, SDIC
Sodium dichlor, dichloro-s-triazinetrione sodium salt (granular chlorine used in swimming pools): 18.1.7
Sodium dichromate
Sodium dihydrogen citrate, C6H7O7Na (anhydrous), NaC6H7O7, C6H7NaO7, HOC(COONa)(CH2COOOH)2
Sodium dihydrogen phosphate
Sodium disulfate (IV), Na2S2O7, sodium metabisulfite, sodium pyrosulfate
Sodium erythrobate monohydrate, C6H7NaO6.H2O, E316 (salt of erythrobic acid, antioxidant)
Sodium ethanoate, sodium acetate
Heat of crystallization of sodium acetate: 24.1.8
Sodium ethoxide, C2H5ONa, Prepare: 16.1.3.1.2
Sodium ferrocyanide E535 (anti-caking agent)
Sodium fluorescein, Xanthene dyes: 7.9.56.1
Sodium fluoride
Sodium formate, sodium methanoate, highly toxic if ingested, forms toxic gases with acids
Sodium fumarate, E3120 (salt of fumaric acid)
Sodium fumarate, E363 (Succinic acid) (acidity regulator, flavour enhancer)
Sodium gluconate, E576 (acidity regulator, sequestrant)
Sodium heptaoxodiphosphate, sodium pyrophosphate
Sodium hexametaphosphate, (NaPO3)6, NaPO3(Na2O), "Calgon", water softener (Also calcium hexametaphosphate)
Sodium hexanitrocobaltate (III), Macallum's stain, sodium cobaltinitrite
Sodium hydride, highly toxic if ingested, corrosive to skin
Sodium hydride, NaH
Sodium hydrogencitrate, HOC(COOH)(CH2COONa)2.1.5. H2O, disodium hydrogen citrate sesquihydrate
Sodium hydrogen carbonate, sodium bicarbonate
Sodium hydrogen glutamate, monosodium glutamate, MSG
Sodium hydrogen glutamate, monosodium glutamate, MSG, intolerance: 19.2.3
Sodium hydrogen phosphate
Sodium hydrogen sulfate, sodium bisulfate
Sodium hydrogen sulfite, sodium bisulfite
Sodium hydrogen tartrate, C4H5O6Na.H2O, C4H5NaO6, NaO2CCH(OH), sodium bitartrate, tartaric acid monosodium salt
Sodium hydrosulfite, Na2S2O4.2H2O, sodium dithionite, toxic by all routes
Sodium hydrosulfite with water, acids, on heating forms sulfur dioxide
Sodium hydrosulfite, Prepare sodium hydrosulfite solution: 5.4.9
Sodium hydroxide
Sodium hypochlorite
Sodium hypophosphite, sodium phosphinate, NaPO2H2, (monohydrate, NaPO2H2·H2O), odourless white crystals
Sodium iodide, NaI, For 0.1 M solution, 15 g in 1 L water, harmful if ingested
Sodium iodide (if I2 makes solution yellow, make colourless by adding sodium hydrogen sulfate)
Sodium iodate
Sodium lactate E325, from milk, salt of lactic acid, humectant, bulking agent, problem lactose intolerant children
Sodium laureth sulfate
Sodium maleate dibasic, E350 (DL-sodium malates (acidity regulator, humectant)
Sodium metabisulfite, sodium pyrosulfite
Sodium methyl p-hydroxybenzoate, E219 (preservative)
Sodium molybdate dihydrate, Na2MoO4.2H2O, For 0.1 M solution, 24.2 g in 1 L water, harmful if ingested
Sodium monofluorophosphate, sensitive toothpaste and Colgate "Triple Action", 1.196 (1450 ppm of Fluoride)
Sodium monopersulfate: 18.1.23 (Swimming pools)
Sodium nitrate
Sodium nitrite
Sodium nitroprusside dihydrate, sodium pentacyanonitrosylferrate (II) or (III), highly toxic if ingested
Sodium nitroprusside dihydrate, forms cyanide vapour when heated, skin irritant
Sodium oleate, cis-9-Octadecenoic acid sodium salt, Oleic acid sodium salt, C18H33NaO2, CH3(CH2)7CH=CH(CH2)7COONa
Sodium orthophenyl phenol, food additive, E232, preservative, anti fungal
Sodium orthovanadate, harmful if ingested, or absorbed through skin (replace with ammonium vanadate)
Sodium oxalate, Na2C2O4, For 0.1 M solution, 13.4 g in 1 L water
Sodium oxalate, sodium ethanedioate, harmful if ingested, skin irritant, toxic fumes when heated
Sodium oxalate, Solution / mixture < 25%, Not hazardous (maximum solubility in water 3.6%)
Sodium p-hydroxybenzoate, E217 (preservative)
Sodium pentachlor phenate, C6Cl5NaO, Poison, used to clean gravestones
Sodium perborate
Sodium percarbonate, Na2CO3.1.5H2O2, 2(Na2CO3.3H2O2, in washing powders
Sodium perchlorate
Sodium perchlorate, toxic if ingested, corrosive to skin, Not permitted in schools
Sodium perchlorate monohydrate, oxidizing agent, explosive mixtures with combustibles and organic compounds
Sodium periodate
Sodium peroxide
Sodium persulfate, Na2S2O8, sodium peroxodisulfate: 18.1.23
Sodium phosphate
Sodium phosphate dibasic, Na2HPO4, disodium hydrogen phosphate
Sodium polyacrylate, Super Expanding Creatures
Sodium potassium tartrate tetrahydrate, E337 (food acid, acidity regulator, stabilizer)
Sodium polyacrylate, acrylic sodium salt polymer, ASAP: 3.3.10, (Ghost crystals)
Sodium polysulfide (photography developer, but should not be stored in schools), harmful if ingested
Sodium polysulfide, photography brown sepia toner, with water or acids forms caustic solutions and H2S gas
Sodium, potassium and calcium salts of fatty acids, E470a (emulsifier, stabilizer)
Potassium sodium tartrate, KNaC4H4O6.4H2O, Rochelle salt
Sodium propionate E281 preservative, in pastry
Sodium pyrophosphate dibasic, Na2H2P2O7, sodium pyrophosphate decahydrate, disodium dihydrogen pyrophosphate
Sodium pyrosulfite, sodium metabisulfite
Sodium saccharin, C7H4NNaO3S.xH2O, 2-Sulfobenzoic acid imide sodium salt, o-Sulfobenzimide sodium salt
Saccharin sodium salt hydrate, Saccharin soluble
Sodium salicylate, sodium 2-hydroxybenzoate
Sodium sesquicarbonate Na2CO3.NaHCO3.H2O occurs as a mineral.
Sodium sesquicarbonate can also be used as a water softener and to remove copper chloride verdigris from old copper vessels.
Sodium silicate
Sodium sorbate (preservative, antifungal): E201
Sodium stearoyl-2-lactylate, E481 (sodium oleylltostearoyl lactylate, emulsifier)
Sodium succinate dibasic hexahydrate, NaOOCCH2CH2COONa.6H2O
Sodium sulfate
Sodium sulfide
Sodium sulfite
Sodium tartrate dihydrate, Na2C4H4O6.2H2O, sodium bitartrate, crystals, sodium (+) tartrate
Sodium tartrate dihydrate, E335 (acidity regulator, sequestrant, food acid), salt of tartaric acid CHOH)2(COOH)2
Sodium tauroglycocholate, surfactant, bile salts, emulsifies fats, sodium taurocholate, Taurocholic acid, [C26,H45NO7S]
Sodium tetraborate, Na2B4O7, borax fused
Sodium tetrathionate dihydrate, Na2S4O6.2H2O, harmful
Sodium thiocyanate, NaSCN, sodium sulfocyanate, test for Fe3+ ions, harmful, toxic fumes when heated
Sodium thioglycolate, C2H3NaO2S, used to find oxygen needs of organisms
Sodium thiosulfate
Sodium thiosulfate pentahydrate
Sodium tripolyphosphate, detergents: 12.6.8
Sodium tungstate, Na2WO4, sodium tungstate dihydrate, source of tungsten
35.20.43 Stilbite, lamellar zeolite, hydrated sodium aluminium silicate, (Geology)
Trisodium phosphate, TSP "sodium phosphate", E339, Na3PO4, Na3PO4.12H2O
Trisodium phosphate (V), sodium orthophosphate, Na3PO4
Trisodium phosphate, Na3PO4.12H2O, For 0.1 M solution, 38 g in 1 L water
12.1.28 Trona, [Na3H(CO3)2.2H2O], Prepare bath salts with sodium carbonate and with sodium sesquicarbonate
35.13.3.1 Ulexite, (Geology)

Soda lime
Soda lime is prepared by dissolving calcium oxide with sodium hydroxide solution, then drying the products.
Its reaction is milder than sodium hydroxide, so is used to avoid violent reactions.
Also, CaO is used with sodium hydroxide to keep it dry because sodium hydroxide is hygroscopic.
Tests for CO2, (if off-white: active, if violet: exhausted).
For anaesthetics, the pH indicator ethyl violet is added to tell whether the soda lime can still absorb carbon dioxide.
The critical pH is 10.3.
It turns from colourless to violet.
Soda lime (NaOH + CaO), granules for absorbing carbon dioxide in respirators
Soda lime, Ca(OH)2 + H2O + NaOH + KOH, Reactions of urea with soda lime: 16.6.16
Soda-lime glass
Soda lime, CaO / NaOH, ACS reagent, granular, +100 mesh particle size
Soda lime, CaO / NaOH, with indicator, pellets
Soda lime, activated, soda lime non-indicating, soda lime self-indicating, (4-14 mesh sizes), ("NaOH + CaO"), mixture of sodium hydroxide and calcium hydroxide
Prepare soda lime: 12.2.1.10

Sodium amalgam
Sodium amalgam, Na(Hg), sodium mercuryamalgam, alloy of mercury and sodium, toxic if ingested
Dispose in beaker of water with iron nail then into a mercury residues bottle
Sodium amalgam with water forms sodium hydroxide, highly corrosive to skin
Sodium amalgam, highly toxic if ingested

Sodium benzoate
Sodium benzoate, C7H5O2Na or C7H5NaO2 or C6H5COONa or NaC6H5COO
Sodium benzoate, benzoic acid sodium salt, sodium benzenecarboxylate, food preservative against yeast and bacteria
It may cause cirrhosis, damage DNA and increase ageing,
It is effective pH 2.5 to 4.2, and used in dyes and antiseptics.

Sodium carbonate
Sodium carbonate, soda ash, washing soda, soda crystals, Na2CO3.10H2O
Sodium carbonate monohydrate, mineral evaporate, Na2CO3.H2O
Calcined soda, anhydrous sodium carbonate, formed by heating sodium hydrogen carbonate, as in last step of Solvay process.
Acids with sodium carbonate: 12.1.25
Alkalis with sodium carbonate: 12.1.9
Dilute hydrochloric acid with sodium carbonate: 12.3.9.2
Expose sodium carbonate decahydrate to the air: 5.0
Heat sodium carbonate crystals: 12.1.24
Hydrolysis of sodium carbonate: 12.10.3
Natron, sodium carbonate decahydrate
Prepare fruit salts, health salts: 16.7.13, "carbonate of soda"
Prepare bath salts:< href="#12.1.28H">12.1.28, sodium carbonate, sodium sesquicarbonate
Prepare hydrogen: 13.3.15
Prepare sodium hydrogen carbonate with sodium carbonate: 12.1.27
Prepare sodium hydrogen carbonate: 12.16.2
Prepare sodium carbonate, LeBlanc: 12.16.8
Prepare sodium carbonate, Solvay: 12.16.7
Prepare standard sodium carbonate solutions: 5.4.6
Remove water hardness: 12.2.5
Sodium carbonate: 18.1.21 (swimming pools)
Sodium carbonate efflorescence: 12.1.23
Sodium carbonate precipitates: 12.1.26
Solid acids, add sodium carbonate: 19.1.3
Washing clothes with washing soda: 19.5.5
Washing powders: 19.6.2
Sodium carbonate
Sodium carbonate, Anhydrous sodiun carbonate, calcined soda, soda ash, Na2CO3
Sodium carbonate decahydrate, natron mineral, washing soda, Na2CO3.10H2O
Sodium carbonate, Na2CO3, sodium carbonate anhydrous, sodium carbonate-10 water, harmful, skin irritant
Sodium carbonate peroxyhydrate, For 0.1 M solution, 28.6 g in 1 L water, Solution < 20%, Not harmful
Sodium carbonate heptahydrate, Na2CO3.7H2O, (not a mineral)
Low cost: from supermarkets as washing soda, from pottery supply stores as soda ash, by heating a thin layer of sodium bicarbonate in the oven for an hour
Sodium carbonate, Na2CO3, calcined soda, carbonic acid disodium salt, soda ash Na2CO3.10H2O, sodium carbonate decahydrate crystals, formerly "nitre" (US niter)
Sodium carbonate, soda crystals, sal soda, crystal carbonate, black ash, trona, E500, colourless or white crystals, odourless powder, hygroscopic
Sodium carbonate is readily soluble in water to form strong alkaline solution.
Sodium carbonate is NOT decomposed by heat (also anhydrous sodium carbonate, soda ash anhydrous, Na2CO3, RD. 2.53, MP. 851 oC), It is used in glass production, softens "hard" water, removes grease, in washing powders and bath salts.
Over half the weight of the crystals is water because of the water of crystallization.
Soda ash is sold as "sodium carbonate".
If sodium carbonate solution is left on the skin it may produce blisters.
Sodium carbonate as washing soda allows sodium ions to displace calcium ions in clay particles.
These clay particles in mud can be dispersed and held in suspension in the washing water and discarded when the washing water is emptied.
Common name: Washing soda, dissolves grease, disinfectant, softens water, cleans stains, absorbs odours, used to prepare dish washing soap.
Use washing soda solution to clean silverware tarnished by eggs by putting in aluminium pan.
Use washing soda solution to remove coffer stains on pottery.

Soda cellulose
Reaction of 18% caustic soda on wood pulp, a mixture of celluloses, to make paper
(C6H10O5)n + NaOH --> [(C6H10O5)2.NaOH]
alpha cellulose + sodium hydroxide --> swollen, insoluble soda cellulose + soluble soda celluloses from other celluloses, hemicelluloses

Sodium chlorate, NaClO3, Not permitted in schools
Sodium chlorate (V), NaClO3, Prepare: 5.4.16
Store sodium chlorate: 3.4.13.10
Sodium chlorate, NaClO3, white solid, crystalline, bleach, weed killer, Oxidizing (OXD 1495)
Sodium chlorate forms violently explosive mixtures with combustibles, organic compounds, ammonium compounds, sulfur, sulfides and finely divided metals.
These explosive mixtures that may detonate from friction, and contact with strong acids by ignition.
Sodium chlorate with concentrated sulfuric acid forms chlorine dioxide gas.
Wood soaked in sodium chlorate becomes explosive.

Sodium chloride
Sodium chloride, NaCl, "salt", table salt, common salt, cooking salt, household salt, rock salt, sea salt, halite
Table salt, "salt"
Table salt may come from a mine or the sea, then dissolved in clean water, then recrystallized to remove any impurity.
Usually, anti-caking chemicals are added, e.g. sodium aluminosilicate or magnesium carbonate or sodium hexacyanoferrate E535.
Iodised salt also contains potassium iodate.
Table salt brands include "Saxa", "Malden Sea Salt".
Each day the body loses about 3g 0f sodium and 3.5.g potassium, to be replaced from food.
Sodium chloride
Sodium chloride (solution), brine, NaCl, For 0.1 M solution, 5.8 g in 1 L water
Basal salt solutions, biology solution: 1.8
Saline tablets, Phosphate buffered saline tablets
Salinity (dissolved salt solutions): 18.2.5
Boiling point of sodium chloride solution: 3.5.1
Common ion effect to precipitate sodium chloride from solution: 17.5.5.3
3.3.1 Ice melts, de-icers
Electric writing, sodium chloride with litmus paper: 11.4.1
Electrolysis of sodium chloride solution: 15.5.12.0
Electrolysis of sodium chloride, Nelson cell: 15.5.13
Flame tests for sodium chloride: 12.1.29
Halite, rock salt, sodium chloride, mineral: 35.20.19, (Geology)
Halide salts with hot concentrated sulfuric acid: 12.19.3.1
Ionic bonds, electrovalent bonds, e.g. sodium chloride: 11.01.1
Low cost: from supermarkets as table salt, or cooking salt, but check whether it has added potassium iodide or anti-caking agents.
However, "popcorn salt" and "kosher salt" do not contain potassium iodide.
Prepare chlorine with sodium chloride: 12.4.1.3
Prepare hydrochloric acid with sodium chloride: 13.3.27
Prepare hydrogen chloride / hydrochloric acid: 13.3.14
Prepare sodium chloride crystals: 12.1.32
Reactions of sodium chloride: 12.19.8.1
Salinity, leaf versus root application of water: 6.55
Sodium chloride, invisible writing ink: 3.2.5.6
Separate sand and salt mixture: 10.3.1
Separate sodium chloride from sodium nitrate: 10.9.1
Separate sodium chloride from iodine: 10.13.1
Sodium chloride solution with copper sulfate solution: 12.1.8
Sulfuric acid with sodium chloride: 12.18.5.6
Table salt and rock salt: 19.1.16
Sodium chloride
Sodium chloride, NaCl, white, cubic crystals (colourless if large), or granules, RD 2.17, MP 804 oC, common salt, table salt,
sodium chloride technical grade, rock salt, halite mineral, sea salt, brine, salt, white cubic crystals.
Sodium chloride is NOT hygroscopic if pure, for chemistry experiments use "uniodized" table salt, which dissolves readily in water to form a neutral solution
Sodium chloride aqueous solution is often called brine.
Sodium chloride is used for cooking and flavouring and food preservative, making butter, curing fish, manufacturing chemicals, e.g. chlorinating swimming pools,
animal licks, wine spills, carpet cleaning.
Sodium chloride is essential in the diet and a supplement is needed after excessive dehydration and sweating.
, However, high intake can cause of high blood pressure, stroke, and heart disease.
Sodium chloride, known as "Canning salt" or "Pickling salt", has no iodine added, unlike table salt.
Use salt, sodium chloride, NaCl, on a piece of lemon to polish brass and copper, sprinkled over spilled wine then vacuum the carpet when dry,
sprinkled over the carpet before vacuuming or sweeping to remove dirt and fluff, to remove stains from teacups, to remove the powder taste of powdered milk.
Use salt + lemon to clean copper
Use salt + vinegar to remove burnt food in aluminium pans
Use salt + water to remove coffee stains on pottery
Use salt + lemon juice to remove rust stains on linen
Use salt to make smokeless candle wicks
The sea is refered to as the "briny", because it is salty like brine

Sodium chlorite
Sodium chlorite, NaClO2, water-purification and bleaching drops "activated" with citric acid.
Fake medicines containing sodium chlorite: solutions known as "Miracle Mineral Supplement", "Master Mineral Solution, MMS", "CD protocol", "Chloriner Dioxide Solution, CDS", are toxic solutions of sodium chlorite, which may be illegally marketed as cure for cancer, HIV, malaria, viruses,
and autism in the form of enemas, after being to be "activated" with citric acid to form chlorine dioxide solution.
These fake medicines can cause vomiting, stomach pains and diarrhea and can be very harmful to children.
12.1.11 Sodium hypochlorite, use in swimming pools

Sodium citrate
Sodium citrate, Na3C6H5O7, sodium citrate dihydrate | Na3C6H5O7.2H2O | HOC(COONa)(CH2COONa)2.2H2O | citric acid trisodium salt dihydrate,
sodium citrate tribasic dihydrate, trisodium citrate dihydrate, crystalline trisodium citrate, trisodium-2-hydroxypropane-1,2,3-tricarboxy (food buffer), E331.

Sodium cobaltinitrite
Sodium cobaltinitrite, Na3Co(NO2)6, yellow-brown crystals or powder, solution decomposes unless acetic acid added, harmful.
Sodium cobaltinitrite, sodium hexanitrocobaltate (III), powerful oxidizing agent, if hot, can start fires if mixed with combustibles.

Sodium dichromate
Sodium dichromate, sodium dichromate dihydrate, Na2Cr2O7.2H2O, sodium bichromate, orange crystalline.
Sodium dichromate, highly toxic if ingested, or skin absorption, carcinogenic.
Sodium dichromate reacts violently with active metals, e.g. Na, Al, Mg, and C, S, P, and easily oxidized organics.
Sodium dichromate, do not isolate and dry chromate precipitates.
Sodium dichromate, toxicity: 3.10.0 Poisons, First Aid
Sodium dichromate, ionization reaction: 12.5.7
Sodium dichromate, Solution < 0.5%, Not hazardous

Sodium dihydrogen phosphate (V)
Sodium dihydrogen phosphate (V), NaH2PO4, Sodium phosphate monobasic, Monosodium orthophosphate
Sodium dihydrogen phosphate, hydrated, NaH2PO4.2H2O, sodium dihydrogen phosphate (V)-2-water, white, odourless, rhombic crystals
It is insoluble in alcohol, slightly deliquescent, anhydrous at 100 oC, in baking powder, food additive, buffers, E339
Sodium phosphate monobasic monohydrate: NaH2PO4.H2O
Sodium dihydrogen phosphate (V), NaH2PO4, monosodium phosphate, MSP, sodium phosphate monobasic, used in plant cell cultures
Prepare sodium dihydrogen phosphate solution: 5.4.17
Prepare baking powder: 19.1.9
Prepare self-leavened flour, "self-raising flour": 19.1.8.1

Sodium ethanoate
Sodium ethanoate, sodium acetate anhydrous, CH3COONa, ethanoic acid sodium salt, sodium acetate trihydrate, CH3COONa.3H2O
For 00.1 M solution, 13.6 g in 1 L water
Sodium ethanoate hydrated, CH3COONa.3H2O, sodium acetate trihydrate, sodium ethanoate-3-water, E262
Sodium acetate, sodium ethanoate, E262 (acidity regulator, preservative), alkaline skin irritant
Sodium acetate with potassium nitrate may explode
Sodium acetate heat pack: 14.1.11
Sodium ethanoate and ethanoic acid: 17.5.2
Sodium ethanoate: 16.1.5.3
Prepare solutions, pH 3 to 11: 12.10.8.0

Sodium fluoride
Sodium fluoride, NaF, highly toxic if ingested, skin irritant
Sodium fluoride with concentrated acids forms hydrofluoric acid, Extremely toxic, Not permitted in schools
Sodium fluoride, Solution < 3%, Not hazardous
Teeth and toothpaste: 9.3.13.1

Sodium bicarbonate
Sodium bicarbonate, NaHCO3, sodium hydrogencarbonate, "bicarb", "baking soda", bicarbonate of soda, nahalite
Sodium hydrogencarbonate, For 0.1 M solution, 8.4 g in 1 L water, with acids forms carbon dioxide
Sodium hydrogencarbonate with citric acid, is sold in "Bomb Bags"
Nahcolite, thermokalite, sodium hydrogencarbonate mineral, NaHCO3, in evaporates
Sodium hydrogencarbonate, bi-carb soda, carb soda, soda lye (saleratus, "aerated salt", "Dwight's saleratus").
Sodium hydrogencarbonate, crystalline, white, odourless monoclinic crystals or granules, alkaline salt, RD 2.16 - 2.22.
Sodium hydrogencarbonate occurs naturally in soda lakes, soda beds.
It decomposes to lose CO2, forms sodium carbonate above 50 oC.
It may be marketed "aluminium free".
About, 2 g of baking soda is neutralized by 24 mL (1 cup), of milk.
Sodium bicarbonate is used in:
Antacids, baking powders, cream of tartar mixes, sourdough, bath salts, burn treatment, cow and cattle feed, degreasers,
Denture cleaning, deodorizers, effervescing health salts, e.g. "Alka-Seltzer", fire extinguishers, and general cleaners.
General neutralizers, kitchen and bathroom cleaners, paint stripping, self-raising flour, soils contaminated with PCBs, toothpaste.
Sodium bicarbonate is a soft white powder that dissolves to a small extent in cold water.
It is decomposed by hot water to form a very weak alkali.
It turns red litmus blue, but is too weak an alkali to affect phenolphthalein.
It is used in cooking as a leavening agent to form bubbles of carbon dioxide to expand bread dough, cake mix and pastry dough, to make them light and nice to eat.
Sodium bicarbonate is used to clean barbecues, children's plastic toys, microwave ovens, and vacuum flasks, to deodorize carpets, refrigerators and shoes.
It is used to freshen dishcloths and laundry towels, to remove fruit juice stains and perspiration from clothing, and to dissolve grease, to soften woollen socks.
Also, add to bath water for relaxing feet soak, precipitate toxic heavy metal ions and neutralize acid wastes before disposal, neutralize acid spills, extinguish fires.
Scientists have found that baking soda can remove far more pesticide from the skin of apples than just tap water or bleach rinse.
Alka-Seltzer
Baking powder: 3.3.4
Experiments
Acids with baking soda, sodium bicarbonate: 12.1.18
Dancing naphthalene mothballs: 3.3.2
Heat baking soda, decomposition: 12.1.17
Heat hydrogencarbonates: 12.16.4
Heat sodium hydrogencarbonate: 12.16.7
Hydrolysis of sodium hydrogencarbonate: 12.10.6
Precipitates from sodium bicarbonate: 12.1.19
Prepare carbon dioxide, heat hydrogencarbonates: 3.4.4
Prepare carbon dioxide, acids with carbonates or bicarbonates: 3.4.1
Prepare carbon dioxide, alum with baking soda: 3.4.2
Prepare carbon dioxide with vinegar and sodium hydrogencarbonate solution: 3.4.6
Simulated boiling: 3.4.7
Soda-acid fire extinguisher: 3.3.1
Sodium bicarbonate, prevents milk from going sour: 12.1.21
Sodium bicarbonate, swimming pools: 18.1.19
Test for sodium bicarbonate in a stomach powder: 12.1.20

Sodium hydrogen phosphate
Sodium hydrogen phosphate, Na2HPO4, sodium monohydrogen phosphate, disodium hydrogen phosphate, sodium phosphate dibasic, standard buffer solutions
Also, sodium hydrogen orthophosphate anhydrous
E450 Diphosphate

Sodium hydrogen sulfate, NaHSO4
Sodium hydrogen sulfate anhydrous, NaHSO4, sodium bisulfate
Sodium hydrogen sulfate, toxic if ingested, corrosive to skin and eyes, heated solution forms sulfur dioxide gas.
Sodium hydrogen sulfate, sodium bisulfate monohydrate, NaHSO4.H2O, sodium hydrogen sulfate monohydrate, deliquescent, anhydrous, nitre cake.
Sodium hydrogen sulfate, sodium bisulfate, swimming pool acid (COR 1821), white crystals, very soluble in water to form acid solution.
It has deliquescent crystals when exposed to the air to eventually form a solution, so keep crystals in a stoppered container.
It can be a substitute for dilute sulfuric acid in some experiments, if preparation requires use of concentrated sulfuric acid use crushed solid sodium hydrogen sulfate.
The solid and the solution are corrosive so handle with care and avoid spills.
If spill occurs, wipe spilled material with wet cloth and neutralize remaining acid with dilute ammonia or baking soda until no acid reaction with blue litmus paper.
Sodium hydrogen sulfate, fused, is Na2S2O7.NaHSO4.
Copper oxide with sodium hydrogen sulfate: 12.3.11
Halide salts with hot concentrated sulfuric acid: 12.19.3.1
Heat sodium bicarbonate: 12.1.17
Iron with sodium hydrogen sulfate: 12.3.13
Magnesium with sodium hydrogen sulfate: 12.3.14
Prepare hydrogen gas: 13.3.15 (See 2.)

Sodium hydrogen sulfite
Sodium hydrogen sulfite, deliquescent, white solid, but dissolves in water to form yellow solution.
With heat, sodium hydrogen sulfite, is decomposed to form sodium sulfate, sulfur dioxide and sulfur, so it is used to sterilize wine casks in the brewing industry.
If KI solutions become yellow from iodine formation, add sodium hydrogen sulfite solution to make solution colourless again.
Sodium bisulfite ACS reagent may be a mixture of NaHSO3 and Na2S2O5.
Sodium hydrogen sulfite, NaHSO3, sodium bisulfite, skin irritant, food additive E222, toxic, use fume cupboard.
Sodium hydrogen sulfite solution (40%), antiseptic and bleach, sterilizer in wine industry.
Sodium hydrogen sulfite with acids forms sulfur dioxide gas.

Sodium hydroxide
Sodium hydroxide, NaOH, ACS reagent, pellets, solid, white rods, pearl, flakes, lumps, granules, very hygroscopic and absorbs CO2 from air,
RD 2.13, MP about 318 oC, caustic soda, soda, soda lye, white caustic, caustic drain cleaner 5%, in "Drano", E524, (emulsifier)
1.22 gm cm-3, cakes if stored for long period, a caustic alkali, pH solution >10, soap making, rayon and paper industry
It is used in experiments for reaction of oxides of Period 3 elements and an analytical reagent, preparing soap and making paper, cleaning cookers
and removing old paint, dissolves grease in drains), very dangerous to eyes, release heat when dissolved in water, must be pure white colour to be pure sodium
hydroxide, store in a bottle with a tightly fitting cork or rubber stopper, NOT glass stoppers or metal screw caps that tend to become cemented to the glass,
solid or solution must NOT be handled because it destroys skin and causes painful blisters, also corrodes clothing.
Treat accidental splashes of sodium hydroxide with plenty of water, then neutralize with vinegar, citric acid or tartaric acid.
Test the part affected with red litmus paper until it fails to turn blue.
Always use sodium hydroxide in dilute solution.
Low cost: hardware stores “crystal drain opener”, check whether it is 100% NaOH, e.g."Drano" contains sodium hydroxide, sodium nitrate, sodium chloride.
Use caustic soda to dissolve grease in a blocked sink, then use a plumber's suction cup.
Extremely toxic if ingested, highly corrosive to skin and eyes, releases heat when dissolved in water
Caustic Soda / Flake / Solid / Pearl 96% Na2CO3
Sodium hydroxide is used as a photography developer replenisher
Sodium hydroxide, > 4 M (16%), Extremely toxic if ingested, highly corrosive to skin and eyes
Sodium hydroxide, < 4 M (16%), Extremely toxic if ingested, highly corrosive to skin and eyes
Sodium hydroxide, < 4 M (16%), > 1 M (4%), toxic if ingested, corrosive to skin and eyes
Sodium hydroxide, > 1 M (4%), > 0.25 M (1%), toxic if ingested, corrosive to skin and eyes
Sodium hydroxide, < 0.25 M (1%), Not hazardous
Sodium hydroxide, 3 M, Dissolve 126 g sticks, 95%, in water and dilute to 1 litre of water
Sodium hydroxide, 4 M, Dissolve 160 g sodium hydroxide in 500 mL water, then dilute to 1 litre of water
Sodium hydroxide, 8.5 M, Dissolve 330 g sodium hydroxide in water, dilute to 1 litre of water (For CO2 absorption)
Sodium hydroxide solution, Etchants: 7.9.20.1
Sodium hydroxide, Prepare sodium hydroxide: 5.4.10
Sodium hydroxide with ammonium, the ammonium reacts with the HO− of sodium hydroxide to give ammonia.
Sodium hydroxide with dilute acids: 12.8.7
Sodium hydroxide with ethyl acetate: 17.3.5
Sodium hydroxide with hydrochloric acid: 12.8.2
Sodium hydroxide with zinc sulfate solution: 12.1.10
Alkalis with metals, sodium hydroxide: 12.1.7H
Alkalis with salts: 12.1.8
Aluminium with sodium hydroxide: 12.1.2
Carbon dioxide with sodium hydroxide solution: 12.13.8
Heat of neutralization: 14.1.5, with a calorimeter
Prepare soap, household soap: 19.3.7
Prepare hydroxides by precipitation: 12.1.33
Prepare hydroxides with ammonia solution: 3.2.1
Rainbow reactions, butyl chloride, sodium hydroxide: 12.1.11
Tests for sodium hydroxide, soapy feel: 12.1.15
Titrate dilute hydrochloric acid with sodium hydroxide solution, with a burette: 12.8.4.0
Titrate dilute hydrochloric acid with sodium hydroxide solution, with a burette (second method): 12.8.4.1

Sodium hypochlorite
Sodium hypochlorite, NaClO, highly toxic by all routes, forms chlorine gas, skin irritant, corrosive
Sodium chlorate (I), domestic bleach, oxidizing agent
Sodium hypochlorite, highly toxic by all routes, forms chlorine gas, skin irritant, corrosive
Sodium hypochlorite solution, 16%, bleach, highly toxic, forms chlorine gas, skin irritant, corrosive
Sodium hypochlorite solution, 5-16%, bleach, highly toxic, forms chlorine gas, skin irritant, corrosive
Sodium hypochlorite solution, < 5%, Not hazardous
Low cost: from supermarkets as laundry bleach having about 6% solution of sodium hypochlorite + sodium hydroxide + "whiteners", scents etc.
For example, Clorox® Regular-Bleach contains sodium hypochlorite, sodium chloride, sodium carbonate, sodium hydroxide, sodium polyacrylate.
The cheapest laundry bleach may be the purest!
Sodium hypochlorite, NaOCl (aq), sodium chlorate (I), domestic bleach, bleaching fluid, e.g. "Chlorox" bleach, oxidizing agent, 12.5% solution, liquid bleach, colourless, strong odour, heat decomposes (4% Cl2), solution (store below 25 oC) (household bleach,domestic bleach,
5% NaOCl, bleaching fluid, disinfecting sinks and drains), chlorine water, chloride of soda, chlorine bleach, water treatment of swimming pools,
highly toxic by all routes, skin irritant, corrosive.
Sodium hypochlorite (aq) bleach evolves chlorine gas that is highly irritant to the lungs.
If acid is added to bleach, large amounts of chlorine are produced, the mixture becomes hot and may boil violently.
Do NOT add concentrated ammonia to bleach.
Do NOT store sodium hypochlorite near acids.
Sodium hypochlorite is a violently unstable liquid, liable to explode without apparent reason.
Sodium hypochlorite can bleach materials like flower petals, leaves and human hair.
Sodium hypochlorite is a good source of chlorine gas for other experiments.
Prepare sodium hypochlorite by adding dilute hydrochloric acid from a dropping funnel to bleach solution in a conical flask fitted with a rubber stopper and gas
collection system, but keep sodium hydroxide solution nearby to stop the reaction.
Sodium hypochlorite, as a very weak solution, may be sold as a gargle, e.g. Milton, but strong solutions are poisonous.
Sodium hypochlorite does NOT exist in solid form.
Sodium hypochlorite with acids forms chlorine gas, toxic.
Sodium hypochlorite, NaOCl, solution 5-16% chlorine bleach, 12.5% solution.
Sodium hypochlorite decomposes in sunlight, store in dark cupboard, bottles in light it may build up pressure and may explode.
Sodium hypochlorite solution, reagent grade, available chlorine 10-15%.
Prepare oxygen gas with bleaching fluid: 12.1.11
Prepare preserving agents for cut flowers: 19.6.5
Prepare sodium dihydrogen phosphate solution: 5.4.17
Prepare sodium chlorate solution: 5.4.16
Prepare sodium hypochlorite: 12.1.13
Reactions of urea with sodium hypochlorite: 16.6.14
Sodium hypochlorite, decomposition, cobalt sulfate catalyst: 17.3.14
"Domestos" solution, NaClO: 9.2.26
12.1.49 Sodium hypochlorite, NaOCl
12.1.10 Sodium hypochlorite bleach

Sodium iodate
Sodium iodate, NaIO3, INaO3, oxidizing agent, causes fire with combustibles or educing agents, iodic acid sodium salt, Preparation: sodium hydroxide + iodic acid,
It is an aqueous solution neutral, and when heated to decomposition it emits very toxic fumes.

Sodium periodate
Sodium periodate, NaIO4, sodium (meta) periodate, harmful, may ignite with combustibles or organics.

Sodium peroxide
Sodium peroxide, Na2O, toxic, corrosive, explosive mixtures with organics, Not permitted in schools

Sodium laureth sulfate
Sodium laureth sulfate, CH3(CH2)11(OCH2CH2)nOSO3Na, sodium lauryl ether sulfate (SLES), (also called "lauryl sulfate"), detergent, surfactant
Sodium lauryl sulfate (SLS), C12H25SO4Na, sodium dodecyl sulfate
Sodium lauryl sulfate (SDS or NaDS), Sodium dodecyl sulfate, harmful, skin irritant, anionic surfactant in cleaning and hygiene products, foam stabilizer
It lowers surface tension to allow bubbles to last longer.
The above inexpensive chemicals are widely used in skin care and personal hygiene products, e.g. shampoos, mouth washes, toothpastes, soaps.
High concentration mays be irritating, but do not cause cancer as reported by unscientific opinions.

Sodium metabisulfite
Sodium metabisulfite, Na2S2O5, (Na-O-(S=O)-O-(S=O)-O-Na), toxic if ingested, skin irritant
Old Nassau flag clock reaction: 17.1.7
Sodium metabisulfite ions, mixture of dithionite ion S2O42- and dithionate ion S2O62-
Sodium metabisulfite, sodium bisulfite, sodium pyrosulfite, disodium metabisulfite, E223, white powder of crystals, reducing agent
Sodium metabisulfite, Hair products: 19.7.3
Sodium metabisulfite, sterilizing "Campden" tablets, home beer-making and wine-making, food preservative, flour treatment agent
Sodium metabisulfite, Prepare: 19.5.6

Sodium nitrate
Sodium nitrate, NaNO3, sodium nitrate (V), nitrate of soda, soda nitre, Chile saltpetre, nitratine, saltpetre
E251 (meat preservative, colour fixative), colourless,
odourless, transparent, trigonal crystals or white granules, RD 2.26, MP 308 oC, deliquescent in moist air
Chile saltpetre from caliche deposits, Chile nitre (agricultural fertilizer), E251
Prepare nitric acid, sulfuric acid with sodium nitrate: 12.5.1
Separate a mixture of sodium chloride and sodium nitrate: 10.9.1

Sodium nitrite
Sodium nitrite, NaNO2, sodium nitrate (III) (OXD HARM 1500), toxic if ingested
Sodium nitrite, white to yellow rhombic crystals or granules, RD 2.17, MP 271 oC, hygroscopic granules (inhibits corrosion), E250
Sodium nitrite, Explosive mixtures with combustibles or organic compounds
Sodium nitrite, Solution / mixture < 1%, Not hazardous
Sodium nitrite, For 0.1 M solution, 7 g in 1 L water, E250 (preservative, colour fixative)
Sodium nitrite with acids forms nitrogen dioxide gas, toxic
Sodium nitrite with phenol, ammonium salts, thiosulfates, cyanides forms explosive explosive mixtures

Sodium perborate
Sodium perborate, sodium perborate monohydrate, sodium perborate tetrahydrate
Bleach, synthetic detergents (syndets): 12.5.1
Sodium perborate monohydrate, BNaO3.H2O, powder, 20-100 mesh, strong oxidizing agent, for non-chlorine bleach detergents
Sodium perborate tetrahydrate, crystals, NaBO3.4H2O, (algicide in swimming pools)

Sodium phosphate
Sodium phosphate, Na3PO4.12H2O, trisodium phosphate (V), TSP, trisodium orthophosphate ("sodium phosphate" Agriculture), sodium phosphate,
tribasic dodecahydrate
Sodium phosphate, Na3PO4, trisodium phosphate, trisodium orthophosphate, hygroscopic
Sodium phosphate, sodium orthophosphate, harmful, corrosive to mucous membranes, alkaline skin irritant
Sodium phosphate, E339 (acidity regulator, emulsifier, mineral salt, laxative, textile fixing agent)
Trisodium phosphate (V)-12-water, tripsa, cleaner
E339Sodium phosphates

Sodium silicate
Sodium silicate solution, Na2O(SiO2)x.xH2O, sodium trisilicate solution, waterglass, soluble glass glassy solid
It is usually sold in strong solution as a thick syrupy liquid that dissolves in water to form an alkaline solution.
Waterglass solidifies on exposure to the air.
Sodium silicate is used as egg preservative, fireproofing fabrics, fresco base.
Sodium metasilicate, Na2SiO3, disodium metasilicate, disodium silicate, sodium silicate, sodium silicon oxide.
Sodium silicate, Na2SiO3, toxic if ingested, alkaline corrosive to skin
Fireproof, cloth, paper, wood: 3.5.11
Prepare sodium silicate precipitates: 12.1.35
Prepare chemical gardens: 12.1.36
Prepare silicic acid and pure silica: 12.1.37
Silicates group, polysilicates, polysilicon: 35.14.1, (Geology)
Sodium silicate, egg preservation: 9.30, (See: 6. Waterglass)
Sodium silicate, waterglass: 7.2.3

Sodium sulfate
Sodium sulfate, Na2SO4, sodium sulfate, threnardite, dyes, mordant, Glauber's salt, mirabilite, salt cake, glauberite mineral
Sodium sulfate (VI)-10-water, Na2SO4.10H2O, sodium sulfate decahydrate, sodium sulfate anhydrous
Sodium sulfate decahydrate, Na2SO4.10H2O, For 0.1 M solution, 32.2 g in 1 L water
Sodium sulfate, anhydrous, granular, Na2SO4, (sodium sulfate decahydrate, crystalline, Na2SO4.10H2O, mirabilite mineral, (rhombic) crystals), hydrated,
white efflorescent crystals that dissolve in water to form a neutral solution, Glare's salt, sal mirabile, cake, former laxative, E514, in many mineral waters.
Sodium sulfate anhydrous Na2SO4, white hygroscopic powder, RD. 2.67, MP 888 oC), (glauberite mineral, Na2Ca(SO4)2, has a bitter and salty taste
(J. R. Glauber 1604-1668, Netherlands).
Prepared by sulfuric acid with common salt, loses water of crystallization in dry air.
Sodium sulfate, Na2SO4.10H2O, Glauber's salt, mirabilite, sodium sulfate, glauberite mineral.
Dyes: 19.4.1
E514 Sodium sulfate (mineral salt) (Health risk, water balance problems)
Electrolysis of sodium sulfate solution: 15.5.21
Halide salts with hot concentrated sulfuric acid: 12.19.2.3
Movement of ions, sodium sulfate solution: 11.5.5
Prepare sodium sulfate crystals: 12.1.38
Titrate dilute sulfuric acid with sodium hydroxide solution, isolate sodium sulfate crystals: 8.4.2
Weight of sulfate radical in sodium sulfate: 17.6.5

Sodium sulfide
Sodium sulfide, Na2S, toxic, Corrosive, Environment danger, highly toxic, alkaline corrosive to skin
Sodium sulfide, forms H2S with strong acids
Sodium sulfide with water forms hydrogen sulfide gas, toxic, Use < 10 mL or 10 g in fume cupboard
Sodium sulfide nonahydrate, Na2S.9H2O, For 0.5 M 120 g in 1 L water
Sodium sulfide, anhydrous. < 30% water of hydration
Sodium sulfide, hydrated, > 30% water of hydration
Sodium sulfide solution, > 95% water of hydration

Sodium sulfite
Sodium sulfite: 18.1.25
Sodium sulfite, hydrated, Na2SO3.7H2O, sodium sulfate (IV)-7-water
Sodium sulfite, anhydrous, Na2SO3, white hexagonal crystals or powder, RD 2.63, alkaline in water (hydrated, sodium sulfate (IV)-7-water, Na2SO3.7H2O, E221
Sodium sulfite with acids forms sulfur dioxide gas
Sodium sulfite can be used to neutralize chlorine or dechlorinate swimming pool water
Sodium sulfite, E221 (preservative in fresh orange juice as decontaminating agent)
Sodium sulfite, Na2SO3.6H2O, For 0.1 M solution, 23.4 g in 1 L water
Sodium sulfite, Na2SO3, sodium sulfite anhydrous, For 0.1 M solution, 12.6 g in 1 L water

Sodium thiosulfate

Sodium thiosulfate pentahydrate
Sodium thiosulfate pentahydrate, Na2S2O3.5H2O, sodium thiosulfate-5-water ("hypo", sodium hyposulfite),
sodium thiosulfate, harmful if ingested, colourless, odourless, monoclinic colourless crystals that dissolve in water to form a neutral solution, or white granules,
molar mass 158.11 g / mol, density 1.67 g / cc, MP 48.3 oC, b.p. 100 oC.
It is soluble in water, efflorescent in dry air, deliquescent in moist air.
It is used in photography for the process of fixing, i.e. dissolving the silver bromide of the exposed plate or film.
Sodium thiosulfate loses water of crystallization at 490 K.
Sodium thiosulfate with acids forms toxic gases on heating.
Sodium thiosulfate, Use small quantities for chemical gardens, crystallization and crystal growth experiments, redox titrations.
Sodium thiosulfate can be used to neutralize chlorine or dechlorinate swimming pool water.
Sodium thiosulfate, Na2S2O3, sodium thiosulfate anhydrous (sodium pentahydrate, Na2S2O3.5H2O, sodium hyposulfite, hypo
Sodium thiosulfate, For 0.1 M solution, 24.8 g in 1 L water, harmful if ingested
Acids with sodium thiosulfate: 12.1.40
Bromine water oxidizes sodium thiosulfate to sodium sulfate and sulfur: 12.1.44
Chlorine water oxidizes sodium thiosulfate to sodium sulfate and sulfur: 12.1.43
Fireproof, cloth, paper, wood: 3.5.11
Heat different crystals: 3.6.1, water of crystallization
Heat of crystallization of sodium thiosulfate: 24.1.7
Heat sodium thiosulfate crystals, Na2S2O3.5H2O: 12.1.39
Heat sodium thiosulfate to form sodium sulfate and sodium pentasulfide: 12.1.46
Hydrogen peroxide with sodium thiosulfate: 17.7.19, ammonium molybdate catalyst
Prepare sodium thiosulfate crystals, "hypo": 12.18.6.1 Prepare sodium thiosulfate crystals, "hypo"
Reactions of copper (II) ions: 12.7.2, (See: 2.)
Reactions of sodium thiosulfate: 12.18.6.2 Reactions of sodium thiosulfate
Reduce copper (II) sulfate to copper sulfide, Cu2S, yellow snowstorm reaction: 12.1.41
Sodium thiosulfate solution, biology solution: 1.11, Prepare
Sodium thiosulfate heat pack: 14.1.13
Sodium thiosulfate, swimming pools: 8.1.26
Sodium thiosulfate with iodine forms sodium tetrathionate and sodium iodide: 12.1.45
Sodium thiosulfate with dilute hydrochloric acid forms sulfur dioxide and sulfur: 12.1.47
Sodium thiosulfate with silver chloride or silver bromide: 12.1.48
Tests for dissolved oxygen, titration: 18.3.3
Tests for free chlorine in water: 18.2.24

12.18.6.1 Prepare sodium thiosulfate crystals, "hypo"
Sodium thiosulfate
Sodium thiosulfate crystals are colourless, efflorescent, monoclinic, that melt at about 48^oC.
1. Put 150 mL of water, 30 g of sodium sulfite and 15 g of crushed sulfur in a 250 mL round bottom flask, fitted with a reflux condenser.
Heat the flask on gauze for three hours.
Filter the solution and evaporate to 30 mL.
Leave to cool and crystallize.
SO3^2- + S (s) --> S2O3^2- (thiosulfite ion = S2O3^2-).
2. Saturate a solution of sodium carbonate with sulfur dioxide.
Na2CO3 + SO2 + H2O --> Na2SO3 + CO2 + H2O
Boil the solution with powdered sulfur
Na2SO3 + S --> Na2S2O3.
3. Prepare sodium thiosulfate supersaturated solution
Add two drops of water to 2 cm of sodium thiosulfate crystals in a test-tube, then heat the test-tube gently over a flame.
When the crystals have dissolved, plug the mouth of the test-tube with cotton wool then leave it to cool.
The contents of the test-tube remain liquid.
Remove the cotton wool and pour the liquid onto a sheet of clean glass.
Drop a tiny crystal of sodium thiosulfate into the liquid on the clean glass.
Crystals form in all directions from the tiny crystal and the liquid becomes completely solid.

12.18.6.2 Reactions of sodium thiosulfate
1. Heat crystals of sodium thiosulfate in a dry test-tube until the crystals begin to melt.
Note water and sulfur as products of the reaction.
Leave the mixture to cool.
Add dilute hydrochloric acid to the residue and note that hydrogen sulfide is given off.
4Na2S2O3 --> 3Na2SO4+ Na2S5
Na2S5 --> Na2S + 4S (s).
2. Add iodine solution to sodium thiosulfate solution.
The iodine loses its colour and thiosulfate ion is converted to tetrathionate ion.
2S2O3^2- + I2 --> S4O6^2- + 2I^- (tetrathionate ion = S4O6^2-).
3. Add chlorine water or bromine water in excess to sodium thiosulfate solution and test with barium chloride solution.
The products are sodium sulfate and sulfur that may be further oxidized to sulfuric acid.
S2O3^2- + Cl2 + H2O --> SO4^2- + S (s) + 2H⁺ + 2Cl^-.
4. Add concentrated hydrochloric acid to sodium thiosulfate solution.
Sulfur precipitates and sulfur dioxide forms.
S2O3^2- + 2H⁺ --> SO2 (g) + H2O + S (s)
Na2S2O3 + 2HCl -->NaCl + H2O + S + SO2
Concentrated hydrochloric acid with sodium thiosulfate solutions
This experiment can be done as a "clock reaction" by reaction of 10 mL of 1M sodium thiosulfate solution with 10 mL of 1 M concentrated hydrochloric acid solution.
Vary the temperature or concentration of the sodium thiosulfate solution and use a stopwatch to measure the time taken for the original colourless mixture to develop a pale yellow colour.
Before the experiment, draw an X on white paper below the conical flask and note the time for the X to disappear.
So as the temperature is increased from 15^oC to 55^oC the X may disappear after 25 to 5 seconds.

12.1.30 Reactions of sodium with water
See diagram 3.73.1: Sodium with water, Sodium in water and under kerosene
Be careful! Check the safety rules in your school system before doing this dangerous experiment
2Na (s) + 2H2O (l) --> 2NaOH (aq) + H2 (g)
sodium + water --> sodium hydroxide + hydrogen gas
This is a type of redox reaction where the oxidation number of the metal increases.
1. Be careful! Check the safety rules in your school system before doing this dangerous experiment.
Use safety glasses and nitrile chemical-resistant gloves.
The reaction of sodium with water is very vigorous because it floats on the surface, fizzes (spits), and melts because of the exothermic reaction, to form a strong
alkaline solution, pH 12-14.
2. The following experiments use a test-tube to observe the reaction of sodium with water, but some teachers use a beaker full of water instead to avoid problems of confining the reaction in a test-tube.
Cover the beaker with wire gauze immediately after adding the sodium.
Do not try to hold the sodium in place on the surface of the water to collect the hydrogen produced because the gas may ignite or explode.
A safe way of demonstrating the reactions of sodium and water is to drop a very small piece of sodium into a swimming pool, and stand back!.
3. Pour a 2 cm layer of kerosene on to the surface of water in a test-tube.
Drop a 3 mm diameter side cube of sodium into the kerosene.
Adjust the layer of kerosene to be shallow enough to allow the top of the sodium to protrude above the surface.
This reaction of sodium with the water is much slower than if the sodium had been dropped directly on to the water.
You can watch the reaction through a magnifying glass held at the side, but never look down into a test-tube.
Sodium metal is lighter than water, but heavier than kerosene.
Be careful! Sodium sinks in the kerosene and floats in the water.
A small area of the sodium suddenly reacts causing a stream of hydrogen bubbles to appear.
The stream of bubbles at one side causes movement.
The irregular shape of the sodium changes to a sphere.
The sodium melts because the reaction gives off heat.
Note any variations in light refraction and reflection below the sodium that suggests something dissolving in the water.
Slight smoke where the hot sodium is above the kerosene level suggests a slight reaction with air.
Test the gas bubbles for oxygen gas or hydrogen gas.
4. Be careful! Use a piece of sodium the size of a wheat grain or rice grain.
Do not point the open end of a test-tube containing sodium at anybody.
The experiment can be done on an overhead projector.
Put water into a Petri dish and add a few drops of phenolphthalein.
Put the Petri dish on an overhead projector.
Use forceps to take a small lump of metallic sodium stored under kerosene and wipe with a piece of filter paper.
Cut a piece of sodium the size of a red bean from the lump and then put it in the Petri dish.
Observe from the screen that the sodium grain floats on the water, melts into a small sphere, moving very rapidly in all directions, becoming smaller and smaller.
At last, the sodium sphere wholly disappears and the solution in the dish also changes its colour from colourless to red.
5. Be careful! Observe the reaction through the side of the test-tube.
Do not look down into the test-tube!.
Put a piece of sodium in 2 cm of water in a test-tube.
Do not point the open end of the test-tube at anybody!.
Test for hydrogen gas with a lighted splint.
Test the contents with litmus paper or phenolphthalein.
The reaction forms sodium hydroxide.
6. Be careful! Observe the reaction through the side of the test-tube.
Do not look down the test-tube!.
Pour a 3 mm layer of kerosene (paraffin oil) on to the surface of water in a test-tube.
Drop a small piece of sodium into the test-tube.
The sodium sinks in the kerosene and floats in the water.
The layer of kerosene should be shallow enough to let the top of the sodium protrude above the surface.
The reaction of sodium with water is much slower than if the sodium had been dropped directly on to the water.
A small area of the sodium suddenly reacts, which causes a stream of bubbles to appear.
The irregular shape of the sodium changes to that of a sphere.
The sodium melts because the reaction forms heat.
Something dissolving in the water below the sodium can be seen.
Some smoke where the hot sodium is above the kerosene level suggests a reaction with air.
Test the gas bubbles for hydrogen gas.
7. Support a short length of glass tubing vertically with one end 2 cm below the surface of water.
Test the water with moist litmus paper.
Add litmus paper to the water.
The upper part of the tube must be quite dry.
Drop a piece of sodium down the tube.
Note the reaction.
Test for hydrogen gas with a lighted splint.
Test the water with litmus paper.
The water becomes alkaline.
2Na (s) + 2H2O (l) --> H2 (g) + 2NaOH (aq)
8. Remove a small lump of sodium from storage under oil.
Observe the layer of oxide / hydroxide on the surface of the sodium.
Cut a pea-size piece from the surface of the sodium.
Observe the shiny sodium metal surface that rapidly darkens because of eaction with air and moisture.
9. Demonstrate the reaction of sodium with water in a fume cupboard or outside if students are protected by a safety shield, or wearing safety glasses.
Use a large beaker filled with water to within 1 cm of the top, so that there is no space for air / hydrogen mixture to accumulate.
Add a piece of sodium no greater in size than a rice grain, 3 mm diameter.
Use a wire gauze on top of the beaker to prevent the ejection of sodium.
The sodium fizzes around the surface of the water for a few seconds, reacting violently.
Add an acid / base indicator to the water, e.g. universal indicator or phenolphthalein, to demonstrate the alkalinity of the reaction products.
Demonstrate the disposal of waste sodium by reaction with ethanol or methylated spirit in a beaker in the fume cupboard as described above.
The sodium and may catch fire with the following reaction:.
Na + H2O--> Na+ + OH- + 1/2H2 (g)
10. Place sodium on wet absorbent paper and observe the ignition of the hydrogen gas.
This experiment can be used to test for the presence of alcohols.

12.1.7 Buffer solutions
1. Hydrochloric acid with sodium acetate in excess, HCl with CH3COONa in excess, i.e. base of a weak acid with strong acid.
2. Sodium hydroxide with acetic acid in excess, NaOH with CH3COOH in excess, i.e. strong base with weak acid in excess.
3. Sodium acetate with acetic acid, CH3COONa with CH3COOH, i.e. base of a weak acid with weak acid.
4. Sodium hydroxide with ammonium chloride in excess, NaOH with NH4Cl in excess.
5 Acidic buffer, e.g. sodium hydrogencarbonate with carbonic acid solutions, the salt of the weak acid is completely dissociated into ions.
The weak acid is only partly dissociated.

12.1.8 Sodium chloride solution with copper (II) sulfate solution
If neither of the possible products of a reaction is insoluble, then the reaction does not occur and go to completion.
The reaction reaches equilibrium with both forward and reverse processes continuing at equal rates.
1. Add sodium chloride solution to copper (II) sulfate solution.
No reaction occurs to completion because the solubility rules show that both possible products, Na2SO4 and CuCl2 are soluble.
The equilibrium only involves ions interacting with the water.
There is no "Na2SO4" as such.
(Na2SO4 + CuCl2) <-->; 2Na+ + SO42-+ Cu2+ + 2Cl-
2. Repeat the experiment with a mixture of sodium nitrate solution and potassium chloride solution.
Nothing happens.
Check potassium nitrate and sodium chloride in the solubility table.

12.1.9 Prepare sodium metal
These experiments are dangerous and are not suitable for school science lessons.
1. Use a ceramic container, e.g. a ceramic light bulb socket.
Insert two steel screws to act as electrodes.
Add sodium hydroxide to the container.
Melt the sodium hydroxide superficially by using a butane torch.
Connect the electrodes to a high current voltage supply.
2. Slices of sodium can be obtained by cutting very thin slices of the sodium while still in liquid paraffin, then wash the slice with hexane.

12.1.10 Sodium hypochlorite bleach.
1. Wet the cork of the bottle of bleaching fluid with the strong solution and touch a piece of red litmus paper.
The red litmus paper first turns blue and then becomes bleached.
Put one drop of blue ink in a test-tube then half fill it with water.
Add one drop of bleaching fluid then shake the test-tube.
The colour from the ink disappears.
2. Wet a strip of coloured cotton cloth then squeeze it nearly dry.
Put the cloth in a beaker then add half a test-tube of the strong bleaching fluid and two test-tubes of water.
Leave the cloth in the liquid for twenty four hours.
If by then the colour has not completely disappeared, renew the bleaching solution and put the cloth in it again.
The cloth is rotted if too strong a bleaching solution is used.

12.1.11 Sodium hypochlorite, use in swimming pools
Sodium hypochlorite is the liquid chlorine for use in swimming pools.
It usually provides 12% to 15% available chlorine and has a pH of 13.
It is generally cheap, but difficult and dangerous to handle.
It also loses its potency rapidly and is usually only used in large swimming pools.
Sodium hypochlorite is stable in alkaline aqueous solutions.
It is sold as 5% solution "laundry bleach", e.g. "Chlorox", and as 12-15% available chlorine
solution, often called "liquid bleach", from pool supply stores.
Sodium hypochlorite, pH of 13 is relatively low in available chlorine concentration, so more is required to maintain the disinfectant residual in swimming pools.
Because of the bulk of its liquid form and its poor storage stability, it must be purchased frequently throughout the swimming pool season.
Although it does not add hardness to the swimming pool, its high pH can contribute to scaling tendencies in hard water areas.
It is generally cheap, but difficult and dangerous to handle.
It also loses its potency rapidly and is usually only used in large swimming pools.
NaOCl + H2O --> Na+ + OCl- + H2O
sodium hypochlorite + water --> sodium ion + hypochlorite ion + water
When dissolved, equilibrium is established between the strong oxidant HClO and the weaker ClO- ion.
HOCl + H2O --> OCl- + H3O+ (Ka = 3 × 10-8)
hypochlorous acid + water --> hypochlorite ion + hydronium ion
HOCl is much more effective in oxidizing the cell contents of bacteria, because the negative charge on OCR- may prevent passage through bacterial walls.
At about pH 6 almost all free chlorine is converted to HOCl.
At pH < 2, chlorine gas forms to corrode metals and pool tile grouting.
CaSO4 (s) --> Ca2+ (aq) + SO42- (aq)
calcium sulfate (in Portland cement) --> calcium ion + sulfate ion
SO42- (aq) + H+ (aq) --> HSO4- (aq)
sulfate ion + hydrogen ion --> hydrogen sulfate ion
However, this can be minimized by adding calcium ions as calcium chloride, CaCl2, to pool water to shift the equilibrium to the left, back to solid calcium sulfate.
Both forms have a high pH, so may require frequent additions of acid to maintain swimming pool water in pH range for chlorine sanitizing, and swimmer comfort.
The hypochlorite ions also establish equilibrium with hydrogen ions, depending on the pH.
The same relative amounts of HOCl and OCl- exist at equilibrium at a given pH if either chlorine gas or hypochlorites are used.
Chlorine decreases the initial pH, and hypochlorites increase the initial pH.
Neither product provides protection against the destructive effects of sunlight on a chlorine residual, so frequent chemical additions and adjustments are necessary.

12.1.15 Tests for sodium hydroxide, soapy feel
Moisten the tip of a finger with a drop of dilute sodium hydroxide solution and rub the fingers together.
The soapy feel is a typical property of strong alkalis.
Wash the fingers immediately after the test.

12.1.17 Heat sodium bicarbonate
Sodium bicarbonate, sodium hydrogencarbonate, "bicarb", "baking soda", bicarbonate of soda, nahalite, NaHCO3
Put 5 g of sodium bicarbonate into a dry test-tube 1.
Put 2 cm of clear limewater in test-tube 2.
Hld test-tube 1 in a paper holder in the left hand so that the test-tube slopes down.
Hold test-tube 2 in the other hand so that the two test-tubes are mouth to mouth.
Heat test-tube 1 over a very flame.
Observe the moisture depositing on the cooler part of the test-tube.
After heating for a few minutes shake up the limewater in test-tube 2.
The limewater turns milky, showing that carbon dioxide is being produced.
Chemical action: sodium bicarbonate + heat --> sodium carbonate + water + carbon dioxide
2NaHCO3 (s) --> CO2 (g) + Na2CO3 (s) + H2O (g)
Na2CO3 (s) --> CO2 (g) + Na2O (s)

12.1.18 Acids with baking soda
Any acid solution causes carbon dioxide to be formed sodium bicarbonate.
Put a 5 mL of baking soda in a test-tube and add vinegar or any other dilute acid.
Dip a lighted taper into the test-tube and it is extinguished by the carbon dioxide formed.

12.1.19 Sodium bicarbonate precipitates
A solution of sodium bicarbonate forms precipitates with metal salts.
These precipitates are not bicarbonates, but the ordinary carbonates of the metals.
Put 2 cm of baking soda solution into a test-tubes and adding drops of the following solutions: copper sulfate, iron (II) sulfate, magnesium sulfate, zinc sulfate.

12.1.20 Tests for sodium bicarbonate in a stomach powder
This mixture may contain calcium carbonate, magnesium carbonate, bismuth carbonate, and sodium bicarbonate, but only sodium bicarbonate is soluble.
Shake 5 mL of the powder with water in a test-tube for a few minutes.
Filter the milky liquid.
The filtrate is a colourless solution of sodium bicarbonate.
Dip the end of a wood splint into the liquid and hold it in the edge of a non-luminous Bunsen burner flame.
The flame turns an intense yellow colour, showing the presence of sodium.
Heat the rest of the solution.
Carbon dioxide forms as shown by testing with limewater.

12.1.21 Sodium bicarbonate prevents milk from going sour
In hot weather milk may turn sour because bacteria change the milk sugar into lactic acid.
So milk that is beginning to go off can be saved by adding sodium bicarbonate solution to it.

12.1.23 Sodium carbonate effflorescence
Put large, clear crystal of sodium carbonate on a watch glass and leave it for an hour.
It forms a white powdery coating that can easily be scraped off with a knife.
This change, called "efflorescence", is caused by the crystal losing its water of crystallization to the air.
The white powder has the chemical formula Na2CO3.H2O, and can be called sodium carbonate monohydrate.

12.1.24 Heat sodium carbonate crystals
Washing soda, Na2CO3.10H2O, sodium carbonate decahydrate, natron, effloresces to form sodium carbonate monohydrate, thermonitrite, Na2CO3.H2O
Heat a crystal of sodium carbonate, gently on a metal lid.
The crystal soon melts.
Continue heating to form clouds of steam.
The liquid dries up and a white powder remains.
The anhydrous sodium carbonate, known as soda ash, has lost all of its water of crystallization.
Na2CO3.10H2O --> Na2CO3 + 10H2O

12.1.25 Acids with sodium carbonate
Sodium carbonate with acids produces effervescence because of formation of carbon dioxide, and the sodium carbonate dissolves.
Observe the reaction of vinegar, citric acid, and dilute sulfuric acid, on sodium carbonate, washing soda, crystals.
2CH3COOH (aq) + Na2CO3 (aq) --> 2CH3COONa (aq) + H2O (l) + CO2 (g)
ethanoic acid + sodium carbonate --> sodium ethanoate + water + carbon dioxide

12.1.26 Sodium carbonate precipitates
1. Add sodium carbonate solution to solutions of copper sulfate, iron (II) sulfate, magnesium sulfate, and zinc sulfate.
In each case double decomposition occurs.
Reaction for zinc sulfate:
zinc sulfate + sodium carbonate --> zinc carbonate + sodium sulfate.
2. Add sodium carbonate solution to alum (hydrated potassium aluminium sulfate), or aluminium sulfate solution.
The precipitate is aluminium hydroxide not aluminium carbonate, because aluminium carbonate is very unstable and is decomposed
by the water to form the hydroxide.

12.1.28 Prepare bath salts
Trona, [Na3H(CO3)2.2H2O], Prepare bath salts with sodium carbonate and with sodium sesquicarbonate
1. Bath salts crystals may be added to bath water to "soften" it.
Sodium carbonate (washing soda), crystals coloured by dyes may be sold as a cheap form of bath salts.
When these bath salts are exposed to the air, they betray their identity by forming a white coating because of efflorescence.
2. Sodium sesquicarbonate (trisodium hydrogencarbonate), Na3H(CO3)2, is a double salt of sodium bicarbonate and sodium carbonate.
It naturally occurs as Na2CO3.NaHCO3.2H2O, the dihydrate evaporate mineral Trona found in evaporation pools.
Better quality bath salts containing of crystals of sodium sesquicarbonate are not so alkaline as washing soda bath salts and are kinder to the skin.
These bath salts are manufactured by combining sodium carbonate and baking soda together, with colouring matter and perfume.
To make bath salt crystals, dissolve 5 g of baking soda in a beaker of hot water.
When the baking soda has dissolved, add four times as much powdered sodium carbonate and stir to dissolve all the powder.
Transfer the solution to an evaporating basin and leave in a hot place until needle-like crystals form.
Unlike washing soda, these crystals are not efflorescent.
Sodium sesquicarbonate can also be used as a water softener and to remove copper chloride verdigris from old copper vessels.

12.1.29 Sodium chloride flame tests
Sodium chloride causes a brilliant gold-yellow colour to a flame.
This is the chemical test for sodium.
"Sodium vapour" lamps are used for lighting roads in towns.
The yellow light of sodium makes a person's face appear bloodless and ghost-like.

12.1.39 Heat sodium thiosulfate crystals, Na2S2O3.5H2O
Use a paper holder to heat crystals of sodium thiosulfate in a dry test-tube.
The crystals first melt then lose their water of crystallization.
With more heating a yellow deposit of sulfur forms in the cooler part of the test-tube and a smell of hydrogen sulfide gas is noted.
Leave the test-tube to cool.
Add drops of an acid solution to the remaining substance, sodium sulfide, and note the strong smell of hydrogen sulfide.

12.1.40 Acids with sodium thiosulfate
Do this experiment near an open window or in a fume hood.
Heat crystals of sodium thiosulfate in a test-tube with citric acid solution or dilute sulfuric acid solution.
Note the sharp, choking smell of sulfur dioxide gas and a milky precipitate of sulfur.
A piece of damp blue litmus paper held at the open end of the test-tube turns red because sulfur dioxide is an acid gas.

12.1.45 Sodium thiosulfate with iodine forms sodium tetrathionate and sodium iodide
2Na2S2O3 + I2 --> Na2S4O6 + 2NaI
With this reaction, sodium thiosulfate is used to remove iodine stains from clothes.

12.1.46 Sodium thiosulfate decomposes to form sodium sulfate and sodium pentasulfide
4Na2S2O3 --> 3Na2SO4 + Na2S5

12.1.47 Sodium thiosulfate with dilute hydrochloric acid forms sulfur dioxide and sulfur
Na2S2O3 (aq) + 2HCl (aq) --> 2NaCl (aq) + S (s) + SO2 (g) + H2O (l)
The sulfur precipitate turns the mixture milky yellow.

12.1.48 Sodium thiosulfate with silver chloride or silver bromide
Sodium thiosulfate treated with silver chloride or silver bromide forms soluble complex, sodium silver thiocyanate, sodium disthiosulfate, argentate (I) complex
2Na2S2O3 + 2AgBr --> Na3Ag(S2O3)2 + NaBr

12.1.49 Sodium hypochlorite, NaOCl.
Sodium hypochlorite is the liquid chlorine for use in swimming pools.
It usually provides 12% to 15% available chlorine and has a pH of 13.
It is generally cheap, but difficult and dangerous to handle.
It also loses its potency rapidly and is usually only used in large swimming pools.
Sodium hypochlorite is stable in alkaline aqueous solution and is available as 5% solution "laundry bleach", e.g. "Chlorox", and as 12-15% available chlorine.
solution, often called "liquid bleach", from pool supply stores.
Sodium hypochlorite, pH of 13, is relatively low in available chlorine concentration so more required to maintain the disinfectant residual in a swimming pool.
Because of the bulk of its liquid form and its poor storage stability, it must be purchased frequently throughout the swimming pool season.
Although it does not add hardness to the swimming pool, its high pH can contribute to scaling tendencies in hard water areas.
It is generally cheap, but difficult and dangerous to handle.
It also loses its potency rapidly and is usually only used in large swimming pools.
NaOCl + H2O --> Na+ + OCl- + H2O
sodium hypochlorite + water --> sodium ion + hypochlorite ion + water
When dissolved, equilibrium is established between the strong oxidant HClO and the weaker ClO- ion.
HOCl + H2O --> OCl- + H3O+ (Ka = 3 × 10-8)
hypochlorous acid + water --> hypochlorite ion + hydronium ion
HOCl is much more effective in oxidizing the cell contents of bacteria, because the negative charge on OCR- may prevent passage through bacterial walls.
At about pH 6 almost all free chlorine is converted to HOCl.
At pH < 2, chlorine gas forms to corrode metals and pool tile grouting.
CaSO4 (s) --> Ca2+ (aq) + SO42- (aq)
calcium sulfate (in Portland cement) --> calcium ion + sulfate ion
SO42- (aq) + H+ (aq) --> HSO4- (aq)
sulfate ion + hydrogen ion --> hydrogen sulfate ion
This can be minimized by adding calcium ions as calcium chloride, to the pool water that shift the equilibrium to the left, i.e. back to solid calcium sulfate, CaSO4.
Both forms have a high pH, and may require frequent additions of acid to maintain swimming pool water in the proper pH range for sanitizing / swimmer comfort.
The hypochlorite ions also establish equilibrium with hydrogen ions, depending on the pH.
The same relative amounts of HOCl and OCl- exist at equilibrium at a given pH if either chlorine gas or hypochlorites are used.
Chlorine decreases the initial pH, and hypochlorites increase the initial pH.
Neither product provides protection against the destructive effects of sunlight on a chlorine residual.
So frequent chemical additions and adjustments are necessary to maintain satisfactory water quality in outdoor swimming pools.

Prepare sodium compounds
Prepare sodium metal: 12.1.9
Prepare standard sodium carbonate solutions: 5.4.6
Prepare standard sodium carbonate solution by dilution: 5.4.9
Prepare sodium hydrogencarbonate: 12.16.2
Prepare soda lime: 12.2.1.10
Prepare sodium carbonate, LeBlanc process: 12.16.8
Prepare sodium carbonate, Solvay process: 12.16.7
Prepare sodium carbonate, LeBlanc: 12.16.8
Prepare sodium carbonate, Solvay: 12.16.7
Solid acids, sodium carbonate: 19.1.16
Prepare soda lime: 12.2.1.10
Prepare sodium ethoxide: 16.1.3.1.2
Prepare salts by neutralization of sodium hydroxide: 12.1.8
Prepare baking powder, sodiumhydrogen carbonate: 19.1.12
Prepare sodium hydrogencarbonate: 12.16.2
Prepare "volcanos" with sodium hydrogencarbonate: 12.16.8
Prepare sodium hydrogen sulfate: 12.10.6
Prepare sodium hypochlorite solution: 15.5.12.6
Prepare sodium hypochlorite bleach: 12.1.10
Prepare permanent crease solution, sodium metabisulfite: 19.4.4
Prepare sodium polyacrylate gels (ghost crystals): 3.3.10
Prepare sodium thiosulfate crystals, "hypo": 12.18.6.1
Prepare sodium thiosulfate solution: 1.11

Silver
See: Silver Table of Elements
See: Silver Elements, Compounds, (Commercial).
Silver
Silver, Ag (Old English siolfor) (Latin argentum, Ag), metal, sheet 30 SWG, strip, sheet, wire, fumes and dust are a heavy metal hazard.
Silver, Ag, is a white transition metal, does not oxidize in air, the best electrical conductor, available as silver wire, occurs as the element.
It is used in coin alloys, electrical conductors, photographic emulsions, jewellery and ornaments.
Silver has low melting point and high malleability, so it is easy to cast and cold forge.
It has almost 100% reflectivity for most of the spectrum except in the violet, so slight yellow tinge.
Reacts with concentrated oxidizing acids, HNO3 or H2SO4 to produce high oxidation number ions, and sulfur dioxide SO2 or nitrogen dioxide, NO2, reacts with concentrated HNO3 and hot concentrated H2SO4.
No reaction with dilute HCl or H2SO4, air, or water.
Silver ions and silver compounds have toxic effects on some bacteria, viruses, algae and fungi, as with heavy metals, but without their toxicity.
So silver was reputed to "sterilize" water.
Formerly, water was kept in silver containers and silver coins were supposed to stop milk spoiling.
Silver has been used to cure smelly socks.
Excess silver can turn the skin blue, argyria.
The "silver paper" used in wrapping paper or in chocolates is usually tin foil, not solver.
Solid silver can be polished to be highly reflective, but silver nanoparticles form a black substance, e.g. in old photographic negatives.
Atomic number: 47, Relative atomic mass: 107.868, RD 10.5, MP = 961 oC, BP = 2210 oC.
Specific heat capacity: 234 J kg-1 K-1.

Strontium
See: Strontium Table of Elements
See: Strontium Elements, Compounds, (Commercial).
Strontium
Strontium, Sr (former Strontia region, Scotland, where Strontium first found), alkaline earth metal, AAS solution.
Toxic if ingested, surface layer corrosive to skin and eyes.
Strontium with water forms hydrogen gas that may explode if mixed with air.
Strontium, do not mix with sulfur or phosphorus, because of dangerous exothermic reaction.
Strontium, Sr, silver white metallic element, in minerals celestine (SrSO4), strontianite (SrCO3), and spring water, similar properties to calcium, salts used for crimson flame in fireworks, after nuclear explosion fallout contains90Sr that can be absorbed in human bone, strontium chloride in toothpaste for sensitive teeth, e.g. "Sensodyne", harder to cut than sodium, use calcium as cheaper alternative, purchase only small quantity and store in tightly-sealed container, give students only few grains per activity.
Atomic number: 38, Relative atomic mass: 87.62, RD 2.54, MP = 800 oC, BP = 1300 oC.
Specific heat capacity: 0.3 J kg-1 K-1.