Question

H-O-H bond angle in H$_2O$ is 104.5$^{\circ}$ and not 109$^{\circ}$ 28' because of

• A. lone pair-lone pair repulsion.
• B. lone pair-bond pair repulsion.
• C. bond pair-bond pair repulsion,
• D. high electronegativity of oxygen.

Answer 1

Answer: (A)

lone pair-lone pair repulsion.

Answer 2

The hybridisation of oxygen in water molecule is sp$^3$, So, water molecule must be tetrahedral and have bond angle 109$^{\circ}$28'. But due to the presence of two lone pair of electrons on oxygen atom (repulsion between Ione pair-lone pair), the bond angle decreases about 104.5$^{\circ}$ and the geometry becomes distorted tetrahedral or V-shaped