When calcium hydroxide is reacted with crystals of ammonium chloride, the products formed as calcium chloride, ammonia and water.
Ca(OH)2+NH4Cl→CaCl2+2NH3+2H2O
When ammonia is reacted with water and excess carbon dioxide, it forms ammonium hydrogen carbonate which on passing through with saturated NaCl solution forms hydrogen carbonate.
NH3+H2O+CO2→NH4HCO3
NH4HCO3+NaCl→NaHCO3↓+NH4Cl
So, the compound A, B, and C are Ca(OH)2,NH3,NH4HCO3 respectively.