Which has maximum vapour pressure
- $\mathrm{HI}$
- $\mathrm{HBr}$
- $\mathrm{HCl}$
- $\mathrm{HF}$
Solution
$\mathrm{HCl} < \mathrm{HBr} < \mathrm{HI} < \mathrm{HF}$
$HCl$ is the most volatile compound among all hydrogen halides. The volatility of a compound is related to its high vapour pressure at ordinary temperature. $HF$ due to hydrogen bonding is least volatile, as the molecular weight increases, intermolecular forces increases due to van der Waals' force of attraction. Thus, $HI$ is liquid and $HCl$ is gas with maximum vapour pressure among all hydrogen halides.
Asked in: JEE-TOPICTESTS-CHEMISTRY