12.13 Identify the reagents shown in bold in the following equations as nucleophiles or electrophiles:
Electrophiles are electron deficient species and can be seeking for an electron pair. On the other hand, the nucleophile is electron rich reagents and they can electron donor(nucleus seeking).
Therefore,
(a) have one lone pair of an electron, electron rich species. So, it is a nucleophile
(b) acts as a nucleus seeking reagent and act as a nucleophile
(c) , it is an electron deficient species, So, it is electrophile.