WAEC Chemistry 2022 Paper

Concept:Oxides of non-metals are generally acidic in nature.Explanation:In the reaction, $\mathrm{CaO}$ is a basic oxide. $\mathrm{SiO}_2$ reacts with $\mathrm{CaO}$ to form the salt $\mathrm{CaSiO}_3$. This behaviour is characteristic of an acidic oxide reacting with a base. Silicon is a non-metal. Therefore, silicon(IV) oxide, $\mathrm{SiO}_2$, is an acidic oxide. Since this is an acid–base reaction and not a redox reaction, $\mathrm{SiO}_2$ is not acting as a reducing or oxidizing agent.Answer:C. an acidic oxide