Question

Salt $A$ commonly used in bakery products, on heating, gets converted into another salt $B$ which itself is used for removal of hardness of water and a gas $C$ is evolved. The gas $C$ when passed through lime water turns it milky. Identify $A,B$ and $C$.

• A. Salt $A$, which is sodium bicarbonate; Salt $B$ is sodium carbonate; $C$ is $C{O}_2$ gas
• B. Salt $A$, which is sodium carbonate; Salt $B$ is sodium bicarbonate; $C$ is $H_2$ gas
• C. Salt $A$, which is sodium bicarbonate; Salt $B$ is sodium carbonate; $C$ is $H_2$ gas
• D. None of these

Answer 1

Answer: (A)

Baking power which is a salt is used as bakery products which give sodium carbonate and carbon dioxide gas on heating. Sodium carbonate is used to remove the hardness of water. Carbon dioxide turns lime water milky.
$NaHC{O}_3$ (Sodium bicarbonate) $\to$ $N{a}_{2}C{O}_3$ (Sodium carbonate) + $C{O}_2$ (carbon dioxide) + $H_{2}O$

Therefore,

• Salt $A$, which is sodium bicarbonate and used as baking powder.
• Salt $B$ is sodium carbonate, which is used to remove the hardness of water.
• $C$ is carbon dioxide gas which turns lime water milky.