Question

$H - O - H$ bond angle in $H _{2} O$ 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 $s p^{3}$. 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 lone pair-lone pair) the bond angle decreases about $104.5^{\circ}$ and the geometry becomes distorted tertrahedral or V-shaped.