Question

Limewater turn milky when carbon dioxide gas is passed through it:

• A. Due to the formation of calcium carbonate.
• B. Due to the formation of calcium hydroxide.
• C. Because hydrogen gas is released.
• D. Because calcium hydroxide reacts with hydrogen gas.

Answer 1

The correct option is A Due to the formation of calcium carbonate.

Limewater is calcium hydroxide solution and it is a base. Carbon dioxide reacts with the calcium hydroxide to form calcium carbonate and water. This can be represented as:

Calcium hydroxide + Carbon dioxide $\to$ Calcium carbonate + Water

Calcium carbonate obtained is white in colour and insoluble in water, hence it makes limewater appear milky.