Question

The boiling points of $HF,HCl,HBr$ and $HI$ follows the order:

• A. $HF>HCl>HBr>HI$
• B. $HF>HI>HBr>HCl$
• C. $HI>HBr>HCl>HF$
• D. $HCl>HF>HBr>HI$

Answer 1

The correct option is B $HF>HI>HBr>HCl$

The boiling point of $HF$ is highest due to hydrogen bonding, i.e., $HF$ exists as associated molecule $(HF{)}_n$. In the rest of the halides, boiling point increases with increase in molar mass aa they do not form hydrogen bonding because of their large size and low electronegativity.