AMU Engineering 2019 solved paper Solved Paper

According to hydrolysis of salts of a weak acid and a weak base, Since, the hydrolysis of such salts will form weak acid and weak base, the solution will be neutral and its pH will be 7 .
Then, B+A−+H2O⇌

HA

Weak‌acid

+

BOH

Weak‌base

Kh=

[HA][BOH]

[B+][A−]

Now, let consider the dissociation of HA and BOH.
HA⇌H++A−
BOH⇌B++OH−
Ka=

[H+][A−]

[HA]

Kb=

[B]+][OH−]

[HA][BOH−]

Also, we know that Kw=[H+][OH−]
Now, put the value of Ka and Kb in above equation.
Kh=

Kw

Ka×Kb

=

[H+][OH−][HA][BOH]

[H+][A−][B+][OH−]

Then kh=

Kw

Ka×Kb