Question

How is washing soda formed

Answer 1

Washing soda is formed by the recrystallisation of sodium carbonate

Na2CO3 +10 H2O => Na2CO3 . 10 H2O

Answer 2

Answer:

Explanation:

Firstly, a cold and concentrated sodium chloride solution is reacted with ammonia and carbon dioxide to obtain sodium hydrogen carbonate.  

The sodium hydrogen carbonate is slightly soluble in water, so it precipitates out as solid.

NaCl +NH3 +CO2 +H2O → NaHCO3 +NH4Cl

Secondly, now sodium hydrogen carbonate is separated by filtration, dried and heated. On heating sodium hydrogen carbonate decomposes to form sodium carbonate. This anhydrous sodium carbonate is known as soda ash.

2NaHCO3 → Na2CO3 +H2O +CO2

The preparation of Sodium Carbonate is also known as Solvay process. But before that calcium carbonate (limestone) was heated to release carbon dioxide.

Thirdly, anhydrous sodium carbonate or soda ash is dissolved in water and recrystallised to get washing soda crystals containing 10 molecules of water of crystallisation.

Na2CO3 + 10H2O → Na2CO3.10H2O

                            Washing Soda