Question

Answer the following:
(i) What happens when crystals of washing soda are left open in dry air?

(ii) Name the change that takes place. Which two industries are based on the use of washing soda?

(iii) With the help of balanced chemical equation, state the reaction that takes place when sodium hydrogen carbonate is heated during cooking.

Answer 1

(i) Sodium carbonate crystallizes from water as decahydrate. It effloresces on exposure to dry air forming the monohydrate.

(ii) Dehydration takes place and we get anhydrous salt. Sodium carbonate is used in glass, soap and paper industries.

(iii) Sodium hydrogen carbonate changes into sodium carbonate with the release of CO₂ gas.