2

Use the concept explained below on each of the reaction to identify the nucleophilic substitution reaction:

In a nucleophilic substitution reaction, the leaving group (nucleophile) is replaced by an electron rich compound (nucleophile). The whole molecular entity of which the electrophile and the leaving group are part is usually called the substrate. The nucleophile essentially attempts to replace the leaving group as the primary substituent in the reaction itself, as a part of another molecule.

Nuc: + R-LG R-Nuc + LG:

The electron pair (:) from the nucleophile (Nuc) attacks the substrate (R-LG) forming a new bond, while the leaving group (LG) departs with an electron pair. The principal product in this case is R-Nucleophile. The nucleophile may be electrically neutral or negatively charged, whereas the substrate is typically neutral or positively charged.

An example of nucleophilic substitution is the hydrolysis of an alkyl bromide, R-Br, under basic conditions, where the attacking nucleophile is the OH - and the leaving group is Br - .

R-Br + OH - R-OH + Br -