Question

$p{k}_a$ of acetic acid and $p{K}_b$ of ammonium hydroxide are 4.76 and 4.75 respectively. Calculate the pH of ammonium acetate solution.

• A. $6.02$
• B. $7.005$
• C. $8$
• D. $5.602$

Answer 1

The correct option is B $7.005$

Ammonium acetate is a salt of weak acid, acetic acid and weak base, ammonium hydroxide.

When weak acid and base is given in a mixture, the $pH$ of ammonium acetate is calculated as:

$pH=7+\frac{1}{2}(p{k}_a-p{k}_b)$

$⟹pH=7+\frac{1}{2}(4.76-4.75)=7.005$