Question

How would you represent hydrogen chloride and hydrochloric acid by chemical formula? Why do they differ? [2 MARKS]

Answer 1

Representation: 1 Mark
Reason: 1 Mark

Hydrogen chloride is represented by HCl(g) while hydrochloric acid is represented by HCl(aq). Hydrochloric acid is prepared by dissolving hydrogen chloride gas in water.
Hydrogen chloride is a covalent compound but when dissolved in water, it ionises to from hydrogen ions and chloride ions, i.e.
$\underset{Hydrochloricacid}{HCl\left(aq\right)}\to \underset{Hydrogenion}{H^{+}\left(aq\right)}+\underset{Chlorideion}{C{l}^{-}\left(aq\right)}$