Question

A solution reacts with crushed egg-shells to give a gas that turns limewater milky

Answer 1

A solution reacts with crushed egg-shells to give a gas that turns limewater milky. Identify the solution . Also give the appropriate chemical reaction. Egg shells contains calcium carbonate, which on reaction with HCl liberates CO2 gas which turn lime water to milky.

Answer 2

The solution is an acid, mainly hydrochloric acid(HCl) or nitric acid(HNO3).

A gas that turns lime water milky is carbon dioxide( CO2), due to the formation of calcium carbonate.

Also, it is known that egg shells predominantly contain calcium carbonate(CaCO3).

Therefore, we need to find a solution that reacts with calcium carbonate to produce carbon dioxide.

Such a solution is hydrochloric acid( HCl) or nitric acid( HNO3).

The reaction is given as follows:

With HCl:

CaCO3 + 2HCl ----------> CaCl2 + H2O + CO2

With HNO3:

CaCO3 + 2HNO3 -----------> Ca( NO3)2 + H2O + CO2