Question

As the concentration of $\left[H^{+}\right]$ of a solution is increased $10$ times, its $pH$:

• A. decreases by one unit
• B. increases by one unit
• C. remains same
• D. none of these

Answer 1

The correct option is A decreases by one unit

pH=- log(H+).

For Example pH of 0.01 N acid solution $=pH=-log\left(0.01\right)=2$.

If its concentration is increased 10 times the it's $pH=log\left(0.1\right)=1$.

So when the concentration of an acid solution is increased by 10 times, its pH will decrease by 1 unit.