Question

Classify the following species into Lewis acids and Lewis bases and show how these act as such: 

(a) HO^– 

(b) F ^– 

(c) H⁺ 

(d) BCl₃

Answer 1

(a) Hydroxyl ion is a Lewis base as it can donate an electron lone pair (OH–). 

(b) Fluoride ion acts as a Lewis base as it can donate any one of its four electron lone pairs. 

(c) A proton is a Lewis acid as it can accept a lone pair of electrons from bases like hydroxyl ion and fluoride ion. 

(d) BCl3 acts as a Lewis acid as it can accept a lone pair of electrons from species like ammonia or amine molecules.