Question

Assertion (A): Among the two $$\mathrm{O}-\mathrm{H}$$ bonds in $$\mathrm{H}{\phantom{A}}_2\mathrm{O}$$ molecule, the energy required to break the first $$\mathrm{O}-\mathrm{H}$$ bond and the other $$\mathrm{O}-\mathrm{H}$$ bond is the same.

Reason (R): This is because the electronic environment around oxygen is the same even after breakage of one $$\mathrm{O}-\mathrm{H}$$ bond.

Options

• A and R both are correct, and R is correct explanation of A.

• A and R both are correct, but R is not the correct explanation of A.

• A is true but R is false.

• A and R both are false.

Answer 1

A and R both are false.

Explanation:

The energy required to break the first $$\mathrm{O}-\mathrm{H}$$ bond is not same than that of the second $$\mathrm{O}-\mathrm{H}$$ bond in water molecule, that means the bond enthalpies of the two $$\mathrm{O}-\mathrm{H}$$ are different. This is because the electronic environment around the oxygen atom in water molecules is not the same even after the $$\mathrm{O}-\mathrm{H}$$ bond breaks.