Question

A solution reacts with crushed egg-shells to give a gas that turns lime-water milky. The solution contains:
a) NaCl
b) HCl
c) LiCl
d) KCl

Answer 1

Correct answer: b) HCl

The eggshells contain ${\text{CaCO}}_3$ which on reacting with $\text{HCl}$ solution gives out a gas that turns lime-water milky.
Hence, the correct answer is option 'b' i.e. HCl.
The reaction can be represented as: ${\text{CaCO}}_3\left(s\right)+\text{2HCl(aq)}\to {\text{CaCl}}_2\left(aq\right)+{\text{H}}_2\text{O(l)}+{\text{CO}}_2\uparrow$