Question

Given below are two statement:
Statement I:
The boiling points of the following hydrides of group $16$ elements increases in the order:
$H_{2}O<H_{2}S<H_{2}Se<H_{2}Te$
Statement II:
The boiling points of these hydrides increase with increase in molar mass.
In the light of the above statements, choose the most appropriate answer from the options given below:

• A. Statement I is incorrect but Statement II is correct
• B. Both Statement I and Statement II are correct
• C. Both Statement I and Statement II are incorrect
• D. Statement I is correct but Statement II is incorrect

Answer 1

The correct option is C Both Statement I and Statement II are incorrect

Both Statements I & II are wrong as $H_{2}O$ has the highest boiling point in the group due to intermolecular hydrogen bonding.

The actual order of boiling points of hydrides group 16 elements is :

$H_{2}S<H_{2}Se<H_{2}Te<H_{2}O$

The rest of the order can be explained on the account of increasing strength of van der waals forces due to increasing size & molar masses.