Sodium chloride

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

Primary

Natural occurrence

  • Sodium chloride occurrs naturally in salt

Hazards

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
NaOH + HCl NaCl + H2O

Testing

Purification

removing 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

Storage

Disposal

See Also

References