The number of species having non - pyramidal shape among the following is ____. (A) $\mathrm{SO}_{3}$ (B) $\mathrm{NO}_{3}^{-}$ (C) $\mathrm{PCl}_{3}$ (D) $\mathrm{CO}_{3}^{2-}$

JEE Main · 2021 · 27 Aug 2021 · Shift 2 · Chemical Bonding and Molecular Structure

The number of species having non - pyramidal shape among the following is ____.
(A)

SO_{3}

(B)

NO_{3}^{-}

(C)

PCl_{3}

(D)

CO_{3}^{2 -}

Answer: 3

A species is non-pyramidal when the central atom carries no lone pair and lies in the plane of its bonds. Sulphur in

S O_{3}

, nitrogen in

N O_{3}^{-}

and carbon in

C O_{3}^{2 -}

each use three bonding domains with no lone pair and are trigonal planar, whereas phosphorus in

PC l_{3}

has one lone pair and is trigonal pyramidal. The number of non-pyramidal species is

3

JEE Main · 2021 · 27 Aug 2021 · Shift 2 · Integer answer