Question

The shape of water molecule which should be tetrahedral has a bent or distorted tetrahedral shape with a bond angle ${104.5}^o$. What could be the reason for this?

• A. $\text{lp-lp}$ repulsion is more than $\text{lp-bp}$ repulsion
• B. $\text{lp-bp}$ repulsion is more than $\text{lp-lp}$ repulsion
• C. $\text{lp-lp}$ repulsion is equal to $\text{lp-bp}$ repulsion
• D. Presence of lone pair does not affect the bond angle

Answer 1

The correct option is A $\text{lp-lp}$ repulsion is more than $\text{lp-bp}$ repulsion

The lone pair of electrons in the oxygen atom is not bonded to any atoms so they are free to repel each other.

These repulsive forces act to push the hydrogen atoms closer together and create a compression angle of $104\cdot 5^{\circ }$,

Due to the special bent shape of the water molecule, this causes the water molecules to build crystal structure when water freezes. Hence water has a unique nature of expanding when it freezes.

so the correct option is [A]