Question

The $p^H$ value of $N/10$ acetic acid solution in which it is 1 percent ionised at this dilution is:

• A. $2$
• B. $1$
• C. $3$
• D. $4$

Answer 1

Answer: (C)

$3$

$C{H}_{3}COOH\rightleftharpoons C{H}_{3}CO{O}^{-}{H}^{+}$

$\frac{1}{10}M$

Molarity $=$ normality because n-factor $=1$

$\left[H^{+}\right]=\frac{1}{10}\times \frac{1}{100}$ (1% dissociation)

$\left[H^{+}\right]={10}^{-3}$

$\therefore pH=-\log \left[H^{+}\right]=3$