Question

Which pair of compounds has the highest and the least boiling point?

• A. $H_{2}O,H_{2}S$
• B. $H_{2}O,H_{2}Se$
• C. $H_{2}S,H_{2}O$
• D. $H_{2}S,H_{2}Se$

Answer 1

The correct option is A $H_{2}O,H_{2}S$

$H_{2}O$ has the highest boiling point among others due to strong hydrogen bonding.

The other three have weak van der Waals forces of attraction which increases with increase in molecular weight.

So, the order of boiling point is: $H_{2}S<H_{2}Se<H_{2}Te<H_{2}O$