In which of the following pairs of molecules/ ions, the central atoms have sp2 hybridisation ?
Explanation
The hybridisation of the central atom can be calculated as
H = $${1 \over 2}\left[ \matrix{
\left( \matrix{
No.\,of\,electrons \hfill \cr
in\,valence\,shell \hfill \cr
of\,atom \hfill \cr} \right) + \left( \matrix{
No.\,of\,monovalent \hfill \cr
atoms\,around \hfill \cr
central\,atom \hfill \cr} \right) \hfill \cr
- \left( \matrix{
Ch{\mathop{\rm arge}\nolimits} \,on \hfill \cr
cation \hfill \cr} \right) + \left( \matrix{
Ch{\mathop{\rm arge}\nolimits} \,on \hfill \cr
anion \hfill \cr} \right) \hfill \cr} \right]$$
$$ \therefore $$ For BF3, H = $${1 \over 2}\left[ {(3) + (3) - (0) + (0)} \right] \Rightarrow 3 \Rightarrow $$ sp2 hybridisation
$$ \therefore $$ For NO2-, H = $${1 \over 2}\left[ {(5) + (0) - (0) + (1)} \right] \Rightarrow 3 \Rightarrow $$ sp2 hybridisation