Question

0.2:

Answer 1

Answer: due to bond pair - lone pair and lone pair -lone pair repulsion

Explanation:

In $NH_3$, nitrogen is the central atom and there are 3 Hydrogens as monovalent atoms.  The number of electron pairs is 4 that means the hybridization will be $sp^3$ and geometry of the molecule will be pyramidal as there are three bond pairs and one lone pair.The bond angle for pyramidal geometry is 107°. The bond angle reduces due to lone pair bond pair repulsions.

 In $H_2O$, oxygen is the central atom and there are 2 Hydrogens as monovalent atoms. The number of electron pairs is 4 that means the hybridization will be $sp^3$ and geometry of the molecule will be bent as there are two bond pairs and two lone pairs.The bond angle for pyramidal geometry is 104.5°.The bond angle reduces further due to greater lone pair-lone pair repulsions.