NEETChemistryChemical Bonding and Molecular Structure
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): The H - O - H bond angle in water is smaller than the H - N - H bond angle in ammonia. Reason (R): The oxygen atom in water possesses two lone pairs of electrons, resulting in greater lone pair - lone pair repulsion which compresses the bond angle more than the single lone pair in ammonia. In the l
Options
- ABoth (A) and (R) are correct and (R) is the correct explanation of (A)
- BBoth (A) and (R) are correct but (R) is not the correct explanation of (A)
- C(A) is correct but (R) is not correct
- D(A) is not correct but (R) is correct
Correct answer
A. Both (A) and (R) are correct and (R) is the correct explanation of (A)
Step-by-step solution
Assertion (A) is correct: The bond angle in water ( H ₂ O ) is 104.5^ , which is smaller than the bond angle in ammonia ( NH ₃ ), which is 107^ . Reason (R) is also correct and explains (A): Both central atoms (O in H ₂ O and N in NH ₃ ) are sp^3 hybridized. However, oxygen has two lone pairs while nitrogen has only one. According to VSEPR theory, the order of repulsive interactions is lone pair - lone pair > lone pair - bond pair > bond pair - bond pair. The strong lone pair - lone pair repulsion in water pushes t