Question

Given below are two statements :
Statement I: The boiling point of hydrides of Group 16 elements follow the order
H₂O > H₂Te > H₂Se > H₂S.
Statement II: On the basis of molecular mass, H₂O is expected to have lower boiling point than the other members of the group but due to the presence of extensive H-bonding in H₂O, it has higher boiling point.
In the light of the above statements, choose the correct answer from the options given below :

• A. Both Statement I and Statement II are true
• B. Both Statement I and Statement II are false
• C. Statement I is true but Statement II is false
• D. Statement I is false but Statement II is true

Answer 1

The Correct Option is A

Two statements are presented:

Statement I: The boiling point order for Group 16 hydrides is H2O > H2Te > H2Se > H2S.

Statement II: Based solely on molecular mass, H2O is predicted to have a lower boiling point than other group members. However, significant H-bonding in H2O results in a higher boiling point.

Select the correct answer based on these statements:

Analysis:

Statement I:

Generally, the boiling points of Group 16 hydrides increase with molecular mass. Water (H2O) is an anomaly due to strong hydrogen bonding. The established order is H2O > H2Te > H2Se > H2S. Therefore, Statement I is accurate.

Statement II:

As indicated, molecular mass alone suggests H2O would have the lowest boiling point. However, extensive intermolecular hydrogen bonding in water substantially elevates its boiling point above that of other hydrides in the group. Consequently, Statement II is also accurate.

Finding:

Both Statement I and Statement II are True.