JAMB Chemistry 2024 Paper

Concept:The general formula $\mathrm{C}_n\mathrm{H}_{2n-2}$ shows a hydrocarbon family with a triple bond, meaning it has two fewer hydrogen atoms than an alkene.Explanation:For a hydrocarbon with $n$ carbon atoms, alkanes have the formula $\mathrm{C}_n\mathrm{H}_{2n+2}$.Alkenes, which contain a double bond, have the formula $\mathrm{C}_n\mathrm{H}_{2n}$.Alkynes, which contain a triple bond, have the formula $\mathrm{C}_n\mathrm{H}_{2n-2}$.Therefore, $\mathrm{C}_n\mathrm{H}_{2n-2}$ corresponds to the alkyne family.For example, when $n = 2$, the formula gives $\mathrm{C}_2\mathrm{H}_2$, which is ethyne, the first member of the alkyne series.Answer:A. alkyne