Question

Draw a labelled diagram to show the preparation of hydrogen chloride gas in laboratory.

Answer 1

Experimental setup for preparation of hydrogen chloride gas in the laboratory:

• Hydrogen chloride gas is collected by the downward delivery (upward displacement of air) as it is 1.28 times heavier than air.
• It is not collected over water, since it is highly soluble in water.
• Hydrogen chloride (HCl) is a colorless gas that forms white fumes of hydrochloric acid (HCl) when brought into contact with atmospheric humidity.

When sodium chloride ($\mathrm{NaCl}$) is treated with concentrated sulphuric acid (${\mathrm{H}}_2{\mathrm{SO}}_4$), we get the products as sodium hydrogen sulphate (${\mathrm{NaHSO}}_4$) and hydrogen chloride ($\mathrm{HCl}$) gas.

$\underset{\mathrm{Sodium}\mathrm{chloride}}{\mathrm{NaCl}\left(\mathrm{s}\right)}+\underset{\mathrm{Sulphuric}\mathrm{acid}}{{\mathrm{H}}_2{\mathrm{SO}}_4\left(\mathrm{l}\right)}\stackrel{<{200}^0\mathrm{C}}{\to }\underset{\mathrm{sodium}\mathrm{hydrogen}\mathrm{sulphate}}{{\mathrm{NaHSO}}_4\left(\mathrm{s}\right)}+\underset{\mathrm{hydrogen}\mathrm{chloride}}{\mathrm{HCl}\left(\mathrm{g}\right)}$