Question

Which of the following is not an electrophile? How is this determined?

`NO_2^+`
`BF_3`
`CH_2=CH_2`
`H^+`

Answer 1

"Electrophiles are positively charged or neutral species having vacant orbitals that are attracted to an electron rich centre. It participates in a chemical reaction by accepting an electron pair in order to bond to a nucleophile"

On the basis of above definition given in the net we can judge which one of the given species is not an eletrophile.

`NO_2^+ and H^+ "positively charged"` so attracted towards ngatively charged centers and hence they are charged electrophiles.

`BF_3->` A neutral molecule but the valence shell of its central atom B is not completely fulfilled.This electron deficiency makes it an electrophile.

`CH_2=CH_2` is neutral molecule but it has got `pi`-bond.So this molecule is capable of donating eletron.Hence does not act as an electrophile.