Question

Identify the Lewis acids and bases in the following reactions:

(i)	BF3	+ N(CH3)3		------	F3B─N(CH3)3
(ii)	PF5	+ F-	-------	PF6-
(iii)	SO2 + N(CH3)3			-------	(CH3)3N─SO2

Answer 1

according to lewis concept, Electron pair acceptor is an acid

and electron pair donar is a base.

1) BF3 + N(CH3)3 ------> F3B---N(CH3)3

since BF3 has empty p orbital so it accepts electrons therefore it is lewis acid

N(CH3)3 has lone pair electron so it donates electrons therefore it is lewis base

2) PF5 + F^- -------> PF6^-

since PF5 has empty d-orbital so it accepts electrons therefore it is lewis acid

F- has electrons so it donates electrons therefore it is lewis base

3) SO2 + N(CH3)3 --------> (CH3)3N----SO2

since SO2 has empty d-orbital so it accepts electrons therefore it is lewis acid

N(CH3)3 has electrons so it donates electrons therefore it is lewis base