Question

Assertion (A) : Among the two $O — H$ bonds in $H_2O$ molecule, the energy required to break the first $O — H$ bond and other $O — H$ bond is the same.
Reason (R) : This is because the electronic environment around oxygen is the same even after breakage of one $O — H$ bond.

• A. A and R both are correct, and R is correct explanation of A.
• B. A and R both are correct, but R is not the correct explanation of A.
• C. A is true but R is false.
• D. A and R both are false.

Answer 1

Answer: (D)

The bond enthalpies of the two $O —H$ bonds in water are not equal. This is because electronic environment around $O$ is not same after breakage of one $O—H$ bond.