The compound that has the largest $\mathrm{H}-\mathrm{M}-\mathrm{H}$ bond angle ( $\mathrm{M}=\mathrm{N}, \mathrm{O}, \mathrm{S}, \mathrm{C}$ ), is

(C) $\mathrm{H}_{2}\mathrm{~S}$

JEE Main · 2020 · 05 Sep 2020 · Shift 2 · Chemical Bonding and Molecular Structure

The compound that has the largest

H - M - H

bond angle (

M = N, O, S, C

), is

Answer: (B)

The

H - M - H

angle is opened by bonding pairs and closed by lone pairs. Water keeps two lone pairs and narrows to about

104. 5^{\circ}

; hydrogen sulphide, with a larger central atom holding its two lone pairs farther out, closes further to about

9 2^{\circ}

; ammonia has one lone pair and opens to about

10 7^{\circ}

. Methane has no lone pairs, so its four bonding pairs spread to the ideal tetrahedral angle of

109. 5^{\circ}

, the largest of the set.

JEE Main · 2020 · 05 Sep 2020 · Shift 2 · Single correct option