JAMB Chemistry 2018 Paper

Concept:The compound that contains aluminum, silicon, oxygen, and hydrogen is a clay mineral.Explanation:Clay is mainly composed of kaolinite.Kaolinite has the formula $\mathrm{Al}_{2}\mathrm{Si}_{2}\mathrm{O}_{5}(\mathrm{OH})_{4}$.This formula shows that it contains aluminum (Al), silicon (Si), oxygen (O), and hydrogen (H).Epsom salt is $\mathrm{MgSO}_{4}\cdot 7\mathrm{H}_{2}\mathrm{O}$, so it does not contain Al or Si.Limestone is mainly $\mathrm{CaCO}_{3}$, so it does not contain Al or Si.Urea is $\mathrm{CO(NH}_{2})_{2}$, so it does not contain Al or Si.Hence, the compound composed of Al, Si, O, and H is clay.Answer:C. Clay