Question

Explain the preparation of acids by displacement of more volatile acids. Explain using chemical equations.

Answer 1

Acids can be prepared by treating a salt of a less volatile acid with a more volatile acid. The more volatile acid displaces the less volatile acid from its salt.

Examples:

\[\ce{NaCl + H2​SO4​ -> NaHSO4​ + HCl ↑}\]

Here, hydrochloric acid (HCl) is more volatile than sulphuric acid, so it is displaced from sodium chloride and escapes as a gas.

Another example:

\[\ce{NaNO3 ​+ H2​SO4​ -> NaHSO4 ​+ HNO3​}\]

Thus, a more volatile acid can be prepared by displacement from its salt using a less volatile acid.