Answer
The formula of alkanes is $\mathrm{C}_{n} \mathrm{H}_{2 n+2},$ and the generic formula for an alkyl halide is $\mathrm{C}_{n} \mathrm{H}_{2 n+1} \mathrm{X}$, where an $\mathrm{X}$ atom replaces a hydrogen atom. When $n=1$, $\mathrm{CH}_{3} \mathrm{X}$ is obtained, followed by $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{X}$ when $n=2$. When $n=3, $ we get $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{X}$ and so on.
Work Step by Step
See answer above.