Chemical Bonding and Molecular Structure Part 3

Concept:The molecule with the highest total number of lone pairs (from its Lewis dot structure) is $\mathrm{NF}_3$.Its central atom (N) has $\mathrm{sp}^3$ hybridisation with one lone pair, giving a bond angle slightly less than the tetrahedral angle.Explanation:Count the total lone pairs in each molecule using Lewis structures:• $\mathrm{HNO}_3$: N has no lone pair; O atoms have 2, 2, and 3 lone pairs → total 7.• $\mathrm{H}_2\mathrm{SO}_4$: S has no lone pair; each O–H and O= gives 2 lone pairs → total 8.• $\mathrm{NF}_3$: N has 1 lone pair; each F has 3 lone pairs → total $1 + 3 \times 3 = 10$.• $\mathrm{O}_3$: Central O has 1 lone pair; terminal O atoms have 2 and 3 lone pairs → total 6.Thus $\mathrm{NF}_3$ (molecule $X$) has the maximum lone pairs (10).Central atom N in $\mathrm{NF}_3$ is $\mathrm{sp}^3$ hybridised with one lone pair.Due to lone‑pair repulsion, the bond angle is reduced from $109.5^\circ$ to about $102^\circ$.Answer:$102^\circ$ (Option B)