A-Level Competing definitions of acids and bases: worked solution

Question

Isopropylamine, (CH3)2CHNH2, is widely used as a feedstock for making insecticides and pharmaceuticals. It acts as a weak base in a way that resembles ammonia. Give one equation showing isopropylamine, (CH3)2CHNH2, behaving as a Brønsted–Lowry base, and a separate equation showing it behaving as a Lewis base. Brønsted–Lowry base: Lewis base:

As a Bronsted-Lowry base it accepts a proton (H+). With water: (CH3)2CHNH2 + H2O = (CH3)2CHNH3+ + OH- As a Lewis base it donates its nitrogen lone pair to form a dative (coordinate) bond with an electron-pair acceptor, e.g. BF3: (CH3)2CHNH2 + BF3 -> (CH3)2CHNH2->BF3 (i.e. (CH3)2CHNH2.BF3)