Question

Give reasons:

Quicklime cannot be used for drying Hydrogen chloride gas.

Answer 1

Quicklime:

Quicklime is a common term for burnt limestone, and Calcium oxide ($\mathbf{CaO}$).

Reason for Quicklime cannot be used for drying $\mathbf{HCl}$ gas:

1. When quicklime is used to dry Hydrochloric acid ($\mathbf{HCl}$) gas, it begins to react with the $\mathbf{HCl}$.
2. It is because $\mathbf{HCl}$ is acid and $\mathbf{CaO}$is a base, that a neutralization reaction occurs between them.
3. They combine to form water and also the calcium chloride salt.
4. As a result, $\mathbf{CaO}$ can never be used to dry $\mathbf{HCl}$ gas.

Quicklime cannot be used for drying $\mathbf{HCl}$ gas because it will start reacting with $\mathbf{HCl}$.