Recrystallization of sodium carbonate gives washing soda. Which of the following are the uses of washing soda?
(A) Manufacturing of borax
(B) Removing the permanent hardness of water
(C) Used in glass, soap and paper industries
(D) Used in soda-acid fire extinguishers
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → (A), (B) and (C) only
Washing soda is sodium carbonate decahydrate, Na2CO3·10H2O.
(A) Manufacturing of borax Correct. Washing soda is used to make other sodium compounds such as borax.
(B) Removing the permanent hardness of water Correct. It turns the dissolved calcium and magnesium salts into insoluble carbonates, which settle out.
(C) Used in glass, soap and paper industries Correct. These are among its main industrial uses.
(D) Used in soda-acid fire extinguishers Incorrect. Soda-acid extinguishers use baking soda (sodium hydrogencarbonate), which reacts with the acid to give carbon dioxide.