In the synthesis of sodium carbonate, the recovery of ammonia is done by treating NH4Cl with Ca(OH)2. The by-product obtained in this process is

1. CaCl2

2. NaCl

3. NaOH

4. NaHCO3


Hint: Acid-Base reaction takes place between NH4Cl, and Ca(OH)2

Sodium carbonate is synthesized by the Solvay ammonia soda process.
The reactions involved are
NH3+H2O+CO2NH4HCO3Ammonium bicarbonateNaCl+NH4HCO3NaHCO3Sodium bicarbonate+NH4Cl2NaHCO3Na2CO3Sodium carbonate+H2O+CO2
NH3 is recovered from NH4HCO3 and NH3Cl formed during the reaction.
NH4HCO3HeatNH3+H2O+CO22NH4ClAmmonium chloride+Ca(OH)22NH3Ammonia+CaCl2Calcium chloride+2H2O