Question

The pH of $0.001( N )$ acetic acid solution, which is $10 \%$ dissociated. is

• A. 3
• B. 1
• C. 4
• D. 2

Answer 1

Answer: (C)

4

Answer 2

Concentration of acetic acid $=0.001 \,N$ for $10 \%$ dissociation, the effective concentration of $H ^{+}$ is one-tenth of total concentration. Therefore concentration $=\frac{1}{10} \times 0.001\, N$ $=0.0001\, N$ $\Rightarrow \,\,\,pH = -\log \left[ H ^{+}\right]=4$