MCQ
When a salt of weak acid and weak base is dissolved in water at $25\,^oC$, the $pH$ of the resulting solution will always
  • A
    be $7$
  • B
    be greater than $7$
  • C
    be less than $7$
  • depend upon $K_a$ and $K_b$ values

Answer

Correct option: D.
depend upon $K_a$ and $K_b$ values
d
For salts of Weak Acid and Weak Base

Hydrolysis constant $\left( K _{ h }\right)=\frac{ K _{ w }}{ K _{ a } \times K _{ b }}$

Degree of hydrolysis, $h=\sqrt{K_h}=\sqrt{\frac{K_w}{K_a \times K_b}}$ when $h\, \ll\, 1$

$pH =\frac{1}{2}\left[ pK _{ w }+ pK _{ a }- pK _{ b }\right]$

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