Question

The pH of two equimolar weak acids are 3.0 and 5.0 respectively. Their relative strength is :

• A. 3:5
• B. 5:3
• C. 100:1
• D. 1:100

Answer 1

The correct option is C 100:1

The relative strength of acids $=$ ratio of hydrogen ion concentration

When $pH=3.0$, $\left[H^{+}\right]={10}^{-3.0}M$

When $pH=5.0$, $\left[H^{+}\right]={10}^{-5.0}M$

The ratio of hydrogen ion concentration $=\frac{{10}^{-3.0}M}{{10}^{-5.0}M}=100:1$

The relative strength of acids is $100:1$