WAEC Chemistry 2022 Paper

Concept:Amphoteric oxides can react with both acids and bases to form salt and water.Explanation:Lead(II) oxide, $\mathrm{PbO}$, is a well-known amphoteric oxide.It reacts with acids such as hydrochloric acid:$\mathrm{PbO + 2HCl \rightarrow PbCl_2 + H_2O}$It also reacts with bases such as sodium hydroxide:$\mathrm{PbO + 2NaOH \rightarrow Na_2PbO_2 + H_2O}$Carbon(II) oxide, $\mathrm{CO}$, is neutral.Nitrogen(IV) oxide, $\mathrm{NO_2}$, is acidic.Calcium oxide, $\mathrm{CaO}$, is basic.Thus, among the given options, lead(II) oxide shows amphoteric behaviour.Answer:C. Lead(II) oxide