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.