WAEC Chemistry 2023 Paper

Concept:The conductivity of an equimolar solution depends on the total number of ions produced per formula unit when the solute dissolves in water.Explanation:Strong electrolytes dissociate completely and produce more ions, so they conduct electricity better than weak electrolytes.$\mathrm{H}_2\mathrm{SO}_4(\mathrm{aq})$ is a strong acid.It dissociates as:$\mathrm{H}_2\mathrm{SO}_4 \rightarrow 2\mathrm{H}^+ + \mathrm{SO}_4^{2-}$This gives a total of $3$ ions per formula unit.$\mathrm{NaOH}(\mathrm{aq})$ dissociates to give $2$ ions: $\mathrm{Na}^+$ and $\mathrm{OH}^-$.$\mathrm{H}_2\mathrm{CO}_3(\mathrm{aq})$ and $\mathrm{CH}_3\mathrm{COOH}_4(\mathrm{aq})$ are weak acids, so they ionise only slightly and produce very few ions.Therefore, for the same molar concentration, $\mathrm{H}_2\mathrm{SO}_4(\mathrm{aq})$ provides the highest concentration of ions in solution.Answer:A. $\mathrm{H}_2\mathrm{SO}_4(\mathrm{aq})$