Question

Explain the reactions that occur during solvay process for the preparation of sodium carbonate

Answer 1

Step 1: Brine solution is saturated with ammonia.

2NH3 + H2O + CO2    →    (NH4)2 CO3

This ammoniated brine is filtered to remove any impurity.

Step 2: Carbon dioxide is reacted with this ammoniated brine to result in the formation of insoluble sodium hydrogen carbonate.

NaCl  +  NH4HCO3  →  NaHCO3  +  NH4Cl

Step 3: The solution containing crystals of NaHCO3 is filtered to obtain NaHCO3.

Step 4: NaHCO3 is heated strongly to convert it into NaHCO3.

2NaHCO3  →  Na2CO3 +  CO2  + H2O

Step 5: To recover ammonia, the filtrate (after removing NaHCO3) is mixed with Ca(OH)2 and heated.

The overall reaction taking place in Solvay process is  2NaCl  + CaCO3  →  Na2CO3 + CaCl2

Answer 2

Step 1: Brine solution is saturated with ammonia.

2NH3 + H2O + CO2    →    (NH4)2 CO3

This ammoniated brine is filtered to remove any impurity.

Step 2: Carbon dioxide is reacted with this ammoniated brine to result in the formation of insoluble sodium hydrogen carbonate.

NaCl  +  NH4HCO3  →  NaHCO3  +  NH4Cl

Step 3: The solution containing crystals of NaHCO3 is filtered to obtain NaHCO3.

Step 4: NaHCO3 is heated strongly to convert it into NaHCO3.

2NaHCO3  →  Na2CO3 +  CO2  + H2O

Step 5: To recover ammonia, the filtrate (after removing NaHCO3) is mixed with Ca(OH)2 and heated.

The overall reaction taking place in Solvay process is  2NaCl  + CaCO3  →  Na2CO3 + CaCl2