The molecular formula of $A$ is $C_{10}H_{18}$ and $B$ is $C_{18}H_{36}$. Name the homologous series to which they belong.

(A) For $A$ $(C_{10}H_{18})$: The general formula for an alkyne is $C_nH_{2n-2}$. Here,$n = 10$,so $2n - 2 = 2(10) - 2 = 18$. Thus,$A$ belongs to the alkyne homologous series.
For $B$ $(C_{18}H_{36})$: The general formula for an alkene is $C_nH_{2n}$. Here,$n = 18$,so $2n = 2(18) = 36$. Thus,$B$ belongs to the alkene homologous series.