Ammonium chloride

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Ammonium chloride
aka Sal ammoniac
Chemical formula NH4Cl
OTP appearance white/clear crystals 
Molar Mass(g/mol) 53.49 
Melting Point(°C) 338(decomp) 
Boiling Point(°C) 520 
Density(g/cc) 1.5274 
Index of refraction 1.642 
Solubility in water(g/L) 383 
Solubility in ethanol(g/L) 4.25 
Solubility in methanol(g/L) 23.7 
Solubility in ether(g/L) insoluble 
Solubility in acetone(g/L) sparingly
NFPA 704
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Uses

Other

Natural occurrence

  • Does occur naturally as the mineral sal ammoniac

Hazards

Production

Extraction

Synthesis

via sodium chloride

Bubble carbon dioxide through a solution of sodium chloride, ammonia, and water, producing ammonium chloride and sodium bicarbonate[1][2][3]:

NaCl(aq) + NH3(aq) + H2O(l) + CO2(g) NaHCO3(s) + NH4Cl(aq)
  1. Prepare an ammonia solution with a density of 0.907 (25% w/w) at 20°C
  2. Heat the solution to 40°C
  3. Add an excess of Salt
  4. Decant/filter solution
  5. Discard residue (undissolved salt)
    Solution is NH4OH + NaCl + NH4Cl + NaOH
  6. Chill to -11°C
  7. Precipitate is ammonium chloride (Approximately 10% w/w of the saturated salt solution)
  8. Solution is NH4OH + NaCl + NaOH with some remaining dissolved ammonium chloride, and weighs approximately 90% of the original saturated salt solution.

via hydrochloric acid

Combine ammonia and hydrochloric acid

NH3 + HCl NH4Cl

via calcium chloride

(or magnesium chloride)

  1. Bubble carbon dioxide through a solution of ammonia and magnesium or calcium chloride, precipitating magnesium or calcium carbonate:
    2 NH3 + CaCl2 + H2O + CO2 2 NH4Cl + CaCO3
  2. Filter
  3. Discard residue
  4. Evaporate filtrate to crystallize ammonium chloride

Purification

Sublimation/dissociation

This could also replace the evaporation iterations in the synthesis. Ammonium chloride dissociates (reversibly) into ammonia and hydrogen chloride at 337.6 °C. If the gasses are cooled on a surface, they react to re-form ammonium chloride, so placing a cold boiling flask over a beaker of solid ammonium chloride, then heating the beaker would transport just the ammonium chloride to the bottom of the flask.

Testing

Storage

Disposal

See Also

References