Sodium chloride

 

Sodium chloride
aka Halite, Salt

Chemical formula	NaCl
OTP appearance	white crystals
Molar Mass(g/mol)	58.44
Density(g/cc)	2.16
Melting Point(°C)	801
Boiling Point(°C)	1413
Solubility in water(g/L)	359
Solubility in ethanol(g/L)	0.65
NFPA 704	0 0 0

Uses

Primary

• WHO LEM
• Necessary for human diet
• Essential feedstock for hydrochloric acid
• Primary source of sodium and chlorine for chemistry

Natural occurrence

• Sodium chloride occurrs naturally in salt

Production

Extraction

from salt

removing magnesium, iron, sulfate, phosphate, carbonate

By adding an excess of calcium hydroxide, magnesium and iron anions precipitate as Mg(OH)₂,Fe(OH)₂,Fe(OH)₃ and the cations SO₄,PO₄,CO₃ precipitate as their calcium salts. See also Lime softening.

1. Produce a warm saturated solution of salt in distilled water
2. Produce a warm saturated solution of calcium hydroxide in distilled water
3. Combine the solutions
4. Cool
5. Bubble carbon dioxide through solution, if necessary
6. Filter
7. Discard residue
8. Evaporate filtrate, containing purer salt

removing bromine and iodine

See the production of bromine and iodine from salt water using chlorine gas.

removing potassium

1. Produce a hot saturated solution of salt
2. Cool until ppt forms.
3. Filter
4. The residue contains all the potassium chloride along with some sodium chloride. Recycle.
5. Evaporate the filtrate
6. The residue is purer salt

Synthesis

• Combine 23g of sodium metal with 35g of chlorine gas in a closed but not sealed container, and ignite. This is a very exothermic reaction.

2 Na + Cl₂ → 2 NaCl

• Combine 36.46g of hydrochloric acid with 40g of sodium hydroxide. This is a very exothermic reaction.

NaOH + HCl → NaCl + H₂O

Purification

Remove sodium iodide

• Wash with propanone. NaI is soluble in acetone, salt is not.

removing magnesium, iron, sulfate, phosphate, carbonate

By adding an excess of calcium hydroxide, magnesium and iron anions precipitate as Mg(OH)₂,Fe(OH)₂,Fe(OH)₃ and the cations SO₄,PO₄,CO₃ precipitate as their calcium salts. See also Lime softening.

1. Produce a warm saturated solution of salt in distilled water
2. Produce a warm saturated solution of calcium hydroxide in distilled water
3. Combine the solutions
4. Cool
5. Bubble carbon dioxide through solution, if necessary
6. Filter
7. Discard residue
8. Evaporate filtrate, containing purer salt

See Also

• Salt