Question

In the laboratory preparation and collection of hydrogen chloride, concentrated sulphuric acid is used as twice- once before the gas is prepared. State the role of conc.suphuric acid in each case.

Answer 1

(i) Hydrogen chloride gas is prepared by treating Sodium chloride with concentrated sulphuric acid. The HCl gas is passed through a drying agent to remove moisture where concentrated sulphuric acid plays the role of dehydrating agent as well.

(ii) NaCl+H

2

SO

4

→NaHSO

4

+HCl(g)