JAMB Chemistry 2023 Paper

Concept:Sodium is a highly reactive alkali metal that displaces hydrogen from water, forming an alkaline hydroxide and releasing hydrogen gas.Explanation:When sodium metal is added to water, it reacts vigorously in a strongly exothermic reaction.The balanced chemical equation is:$$2\mathrm{Na}(s) + 2\mathrm{H}_2\mathrm{O}(l) \rightarrow 2\mathrm{NaOH}(aq) + \mathrm{H}_2(g)$$Sodium replaces hydrogen from water because sodium is more reactive than hydrogen.The products formed are sodium hydroxide, $\mathrm{NaOH}$, which dissolves in water, and hydrogen gas, $\mathrm{H}_2$, which escapes as bubbles.Thus, the reaction produces sodium hydroxide and hydrogen gas only.Answer:C. Sodium hydroxide ($\mathrm{NaOH}$) and hydrogen gas ($\mathrm{H}_2$).