JEE Main 2025 Jan 22 Shift 2, Chemistry Q1: Valence Shell Electron Pair Repulsion (VSEPR) Theory

The experimental dipole moments (in Debye) for these molecules are:

$N{F}_3$: $0.24D$, $HBr$: $0.79D$, $H_{2}S$: $0.95D$, $CHC{l}_3$: $1.04D$.

$N{F}_3$ has an unusually small dipole because the resultant of the three N$\to$F bond moments points opposite to the lone-pair contribution on nitrogen, leading to large cancellation. $HBr$ is a simple polar diatomic with moderate polarity. In $H_{2}S$ the two S$-$H bond dipoles add vectorially to give a slightly larger net moment. $CHC{l}_3$ has three strongly polar C$-$Cl bonds whose components along the C$-$H axis add constructively, giving the largest moment.

$\therefore$ Increasing order: $N{F}_3<HBr<H_{2}S<CHC{l}_3$.