(a) Acetaldehyde $(\mathrm{CH}_3\mathrm{CHO})$ is a member of aldehyde series.(b) Ethyne $(\mathrm{C}_2\mathrm{H}_2)$ is the first member of the alkyne family, with two carbon atoms connected by a triple bond. Alkynes comprise a series of carbon and hydrogenbased compounds that contain at least one triple bond. This group of compounds is a homologous series with the general molecular formula of $\mathrm{C}_n\mathrm{H}_{2n-2'}$, where $n$ equals to any integer greater than one.(c) Ethyne $(\mathrm{C}_2\mathrm{H}_2)$ have two carbon atoms connected by a triple bond.(d) $\mathrm{C}_3\mathrm{H}_7\mathrm{OH}$ belongs to the homologous series with general formula of$\mathrm{C}_n\mathrm{H}_{(2n+1)}\mathrm{OH}$The first member of this series is$\mathrm{C}_1\mathrm{H}_{(2(1)+1)}\mathrm{OH} = \mathrm{CH}_3\mathrm{OH} \; ext{ methanol. }\;$