Question

H₃BO₃ is

(a) monobasic acid and weak Lewis acid

(b) monobasic and weak Bronsted acid

(c) monobasic and strong Lewis acid

(d) tribasic and weak Bronsted acid.

Answer 1

The correct option (a) monobasic acid and weak Lewis acid

Explanation:

Central boron atom in H₃BO₃ is electron deficient, therefore it accepts a pair of electron, hence it is weak Lewis acid. There is no d-orbital of suitable energy in boron atom. So, it can accommodate only one additional electron pair in its outermost shell. Thus, H₃BO₃ is a monobasic weak Lewis acid.

H₂O(base) + B(OH)₃(acid) →[B(OH)₄]^- + H⁺