Q. Which of the following pairs are correctly matched?

1. Bleaching powder — Oxidising agent in chemical industries
2. Baking powder — A mixture of sodium hydrogen carbonate and a mild edible acid
3. Washing soda — Removes permanent hardness of water

Select the correct answer using the codes below:
Answer: 1, 2 and 3
Notes: Bleaching powder acts as an oxidising agent in chemical industries. Baking powder comprises sodium hydrogen carbonate and a mild edible acid such as tartaric acid. Washing soda (sodium carbonate) is used to remove permanent hardness of water by precipitating calcium and magnesium ions. All three pairs are correctly matched as per their chemical uses.