AIPMT 2010 Physics and Chemistry Paper

For sp2 hybridisation, there must be 3σ-bonds or 2σ-bonds along with a long pair of electrons.
(i) NO2‌−⇒2σ+1ℓp=3, i.e., sp2 hybridisation
(ii) NH3⇒3σ+1ℓp=4, i.e., sp3 hybridisation
(iii) BF3⇒3σ+0(p=3., i.e., sp2 hybridisation
(iv) NH2−⇒2σ+2(p=4., i.e., sp3 hybridisation
(v) H2O⇒2σ+2(p=4., i.e., sp3 hybridisation
Thus, among the given pairs, only BF3 and NO2‌− have sp2 hybridisation.