Question

If $H^{+}$ ion concentration of a solution is increased by $10$ times, its $pH$ will :

• A. increase by one
• B. remains unchanged
• C. decrease by one
• D. increase by $10$

Answer 1

The correct option is C decrease by one

The hydrogen ion concentration is increased by 10 times.

Thus ratio of hydrogen ion concentration is $\frac{[H^{+}{]}_2}{[H^{+}{]}_1}=10$.

Change in pH is $\Delta pH=p{H}_2-p{H}_1=-log\frac{[H^{+}{]}_2}{[H^{+}{]}_1}=-1$.

Thus pH will decrease by 1.