Question

Lime water turns milky when carbon dioxide gas is passed through it due to the formation of _________.

• A. calcium
• B. calcium dioxide
• C. calcium carbonate
• D. water

Answer 1

The correct option is C calcium carbonate

When carbon dioxide passed through lime water it turns milky solution. This is due to the insoluble suspension of calcium carbonate ($CaC{O}_3$) formed which is 'white' in colour. Calcium carbonate is insoluble in water and settles to the bottom after some time.

The chemical reaction involved is:

$Ca\left(OH{)}_2\right(aq)+C{O}_2(g)⟶CaC{O}_3(s)+H_{2}O(l)$