Assertion : The H - O - H bond angle in H ₂ O is smaller than the H - N - H bond angle in NH ₃ . Reason : The oxygen atom in water has two lone pairs of electrons which exert greater repulsion on the bond pairs compared to the single lone pair on the nitrogen atom in ammonia.

Step-by-step solution

In H ₂ O , the central oxygen atom is sp^3 hybridized and possesses two lone pairs and two bond pairs. The H - O - H bond angle is approximately 104.5^ . In NH ₃ , the central nitrogen atom is also sp^3 hybridized but possesses one lone pair and three bond pairs. The H - N - H bond angle is approximately 107^ . Thus, the H - O - H bond angle is smaller than the H - N - H bond angle, making the Assertion true. According to VSEPR theory, lone pair-lone pair repulsion is stronger than lone pair-bond pair repulsion. Th