question_answer

In which of the following molecules/ions \[B{{F}_{3}},\,NO_{2}^{-},\,NH_{2}^{-}\] and \[{{H}_{2}}O\], the central atom is sp2 hybridised?                                                                                                   [AIPMT (S) 2009]

A)  \[NO_{2}^{-}\] and\[NH_{2}^{-}\]

B)       \[NH_{2}^{-}\] and \[{{H}_{2}}O\]

C)  \[NO_{2}^{-}\] and \[{{H}_{2}}O\]

D)       \[B{{F}_{2}}\] and \[NO_{2}^{-}\]

Correct Answer: D

Solution :

Key Idea For \[\to \]hybridisation, there must be either \[\to \]bonds or \[\to \]bonds and one lone pair of electrons in the molecule or ions.

\[\to \]bonds, ie, \[\to \]hybridization

\[\to \]bonds +1 lone pair of electrons ie, \[\to \]hybridisation

\[\to \] bonds +2 lone pairs, ie, \[\to \]hybridization

\[\to \]bonds +2 lone pairs, ie, \[\to \]hybridization

Thus, in \[\to \]and \[\to \]central atom is sp2 hybridised.