Question

pH range of boric acid and borax buffer
mixture is
(A) 2.2-3.8 (B) 6.8 - 9.2
(C) 5.9-8.0 (D) 4.0-6.2​

Answer 1

answer : option (B) 6.8 - 9.2

explanation : first of all, understand the nature of boric acid and borax (or sodium borate ).

boric acid is very weak acid in nature. Although it doesn't have hydronium, it is considered as acid because in water it attaches with OH- and makes B(OH)⁴- anion. that's why it is an acid.

now, borax is a sodium salt of boric acid.

as boric acid is weak acid so, it makes strong conjugate base. when borax dissolved in water, is hydrolyzed to boric acid and OH− anions, yielding a pH of about greater than 9.

here, option (B) satisfied both, boric acid and borax buffer mixture so, option (B) should be correct choice.

Answer 2

Answer:

option (b)

I think so thankyou