Question

What will be the $pH$ of $0.1\, M$ ammonium acetate solution? $\left(p K_{a}=p K_{b}=4.74\right)$

• A. 4.74
• B. 6.74
• C. 7.74
• D. 7

Answer 1

Answer: (D)

7

Answer 2

Ammonium acetate $\left( CH _{3} COONH _{4}\right)$ is a salt of weak acid and weak base.
$p H=7+\frac{1}{2}\left(p K_{a}-p K_{b}\right)$
Given that, $p K_{a}=p K_{b}=4.74$
Putting that values, we get
$p H=7+\frac{1}{2}(4.74-4.74)=7+0=7$