Electrophile is a species that forms bonds with nucleophiles by accepting an electron pair. because electrophiles accept electrons, they are Lewis acids. CN−is nucleophile, which is electron rich in nature and electrophile is electron deficient in nature and contain positive charge. BF3= Neutral electrophile or Lewis acid (electron deficient) NO2+= Electrophile AlCl3= Electrophile (electron deficient) Hence, only CN−is not an electrophile.