In which of the following pairs of molecules/ions, the central atoms have sp²-hybridisation?

Options

(a) NO₂⁻ and NH₃
(b) BF₃ and NO₂⁻
(c) NH₂⁻ and H₂O
(d) BF₃ and NH₂⁻

Correct Answer:

BF₃ and NO₂⁻

Explanation:

For sp² -hybridisation, there must be 3 σ bonds or 2 σ bonds along with a lone pair of elctrns.
NO₂⁻ ⇒ 2σ + 1/p = 3 i.e.,sp² -hybridisation
NH₃ ⇒ 3σ + 1/p = 4 i.e.,sp³ -hybridisation
BF₃ ⇒ 3σ + 0/p = 3 i.e.,sp² -hybridisation
NH₂⁻ ⇒ 2σ + 2/p = 4 i.e.,sp³ -hybridisation
H₂O ⇒ 2σ + 2/p = 4 i.e.,sp³ -hybridisation
Thus, among the given pairs, only BF₃ and NO₂⁻ have sp² -hybridisation