WAEC Chemistry 2014 Paper

Concept:Salts formed from a weak acid and a strong base hydrolyse to give an alkaline solution.Explanation:Sodium ethanoate, $\mathrm{CH_3COONa}$, is such a salt because it comes from ethanoic acid, $\mathrm{CH_3COOH}$, a weak acid, and sodium hydroxide, $\mathrm{NaOH}$, a strong base.When dissolved in water, the ethanoate ion reacts with water:$$\mathrm{CH_3COO^- + H_2O \rightleftharpoons CH_3COOH + OH^-}$$The release of hydroxide ions, $\mathrm{OH^-}$, makes the solution alkaline.The other salts, $\mathrm{NH_4Cl}$, $\mathrm{AlCl_3}$ and $\mathrm{NH_4NO_3}$, are derived from strong acids and weak bases, so their hydrolysis produces acidic solutions.Answer:C. $\mathrm{CH_3COONa_{(s)}}$