Which from following alkyl halides has highest boiling point?
Which from following alkyl halides has highest boiling point?
$\mathrm{CH}_3 \mathrm{~F}$
$\mathrm{CH}_3 \mathrm{Cl}$
$\mathrm{CH}_3 \mathrm{Br}$
$\mathrm{CH}_3 \mathrm{I}$
Solution
Within alkyl halides, for a given alkyl group, the boiling point increases as magnitude of van der Waals force increases with increase in size and mass of halogen.
Thus, boiling point of alkyl halide decreases in the order, $\mathrm{CH}_3 \mathrm{I}\gt\mathrm{CH}_3 \mathrm{Br}\gt\mathrm{CH}_3 \mathrm{Cl}\gt\mathrm{CH}_3 \mathrm{~F}$.
$\mathrm{CH}_3 \mathrm{I}$ has the highest boiling point.