Question

Consider the following statements:
Statement-I: H$_2$Se is more acidic than H$_2$Te.
Statement-II: H$_2$Se has higher bond dissociation enthalpy than H$_2$Te.
In light of the above statements, choose the correct option:

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

Hint:

When comparing the acidity of hydrides in Group 16, remember that as you move down the group, the bond dissociation enthalpy decreases and acidity increases due to the larger atomic size.

Answer 1

The Correct Option is D

Step 1: Analysis of Statement-I (Acidity of H\(_2\)Se and H\(_2\)Te)
Acidity of Group 16 hydrides increases down the group due to a weakening H-chalcogen bond from increasing atomic size.
This facilitates easier H\(^+\) dissociation, resulting in greater acidity.
Consequently, H\(_2\)Te should be more acidic than H\(_2\)Se because Te is larger than Se.Statement-I is false as H\(_2\)Te exhibits higher acidity than H\(_2\)Se.
Step 2: Analysis of Statement-II (Bond Dissociation Enthalpy)
Bond dissociation enthalpy is the energy needed to break a bond.
Larger central atoms generally lead to lower bond dissociation enthalpies.
For H\(_2\)Se and H\(_2\)Te, the H-Te bond is weaker than the H-Se bond due to Te's larger size. Therefore, H\(_2\)Se possesses a higher bond dissociation enthalpy than H\(_2\)Te.Statement-II is false because H\(_2\)Se has a higher bond dissociation enthalpy than H\(_2\)Te.
Step 3: Conclusion
Both statements are false.
The correct option is (4).