WAEC Chemistry 2025 Paper

Concept:An amphoteric oxide reacts with both acids and bases to form salt and water.Explanation:Among the given oxides, only beryllium oxide ($\mathrm{BeO}$) is amphoteric.The oxides of calcium, magnesium, and barium are basic metallic oxides.Beryllium oxide reacts with an acid as a base:$$\mathrm{BeO + 2HCl \rightarrow BeCl_2 + H_2O}$$It also reacts with a base as an acid:$$\mathrm{BeO + 2NaOH \rightarrow Na_2BeO_2 + H_2O}$$Therefore, $\mathrm{BeO}$ shows both acidic and basic character.Answer:D. $\mathrm{BeO}$