Question

Given below are two statements: 
Statement I: $ H_2Se $ is more acidic than $ H_2Te $ 
Statement II: $ H_2Se $ has higher bond enthalpy for dissociation than $ H_2Te $
In the light of the above statements, choose the correct answer from the options given below.

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

Hint:

- Remember the periodic trend: acidity of hydrides increases down the group - Bond enthalpy decreases with increasing atomic size in a group - Larger atoms form weaker bonds, making their hydrides more acidic

Answer 1

The Correct Option is A

Analysis of Statement I:
- Acidic character increases down the group for hydrides (H₂O < H₂S < H₂Se < H₂Te) - H₂Te is more acidic than H₂Se because:

• Te is larger than Se, making Te-H bond weaker
• H⁺ ion is more easily released from H₂Te

- Therefore, Statement I is false

Analysis of Statement II:
- Bond enthalpy decreases down the group (H-Se > H-Te)
- H₂Se has higher bond dissociation enthalpy because: 

• Se is smaller than Te, forming stronger bonds
• Bond strength decreases with increasing atomic size

- Therefore, Statement II is true