Hydrolysis of which of the following compounds liberates an acidic gas?

Which one of the following reactions does not come under hydrolysis type reaction?

At atmospheric pressure and very low temperature,water crystallises to

Statements about heavy water are given below.
$A.$ Heavy water is used in exchange reactions for the study of reaction mechanisms.
$B.$ Heavy water is prepared by exhaustive electrolysis of water.
$C.$ Heavy water has higher boiling point than ordinary water.
$D.$ Viscosity of $H_2O$ is greater than $D_2O$.

What is 'plumbo solvency' referring to in the context of lead?

When zeolite (hydrated sodium aluminium silicate) is treated with hard water,the sodium ions are exchanged with: