Question

Give reason: Hydrogen Chloride gas cannot be dried over quick lime.

Answer 1

• We know that Hydrogen chloride is acidic in nature whereas quick lime i.e. Calcium oxide is basic in nature.
• If we use Calcium oxide for drying, then both will react to form a salt.
• The reaction is shown below.
  $$\begin{gathered} 2\mathrm{HCl}\left(\mathrm{aq}\right)+\mathrm{CaO}\left(\mathrm{aq}\right)\to {\mathrm{CaCl}}_2\left(\mathrm{aq}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right) \\ \mathrm{Hydrochloric}\mathrm{Calcium}\mathrm{Calcium} \\ \mathrm{acid}\mathrm{oxide}\mathrm{chloride} \end{gathered}$$
• Therefore, quick lime is not used for drying Hydrogen chloride gas.