Question

Which of the following has lowest boiling point?

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

Answer 1

The correct option is B $H_{2}S$

Boiling point is dependent on van der-wall forces of attraction which directly proportional to molar mass.

$H_{2}S$ has the lowest boiling point.
The correct order of boiling points is $H_{2}S<H_{2}Se<H_{2}Te<H_{2}O$
The boiling point of $H_{2}O$ is maximum due to hydrogen bonding.
On moving down the group, the boiling point increases.