Question

How is the concentration of hydronium ions ($H_3{O}^{+}$) affected when a solution of an acid is diluted?

Answer 1

When given amount of acid is added to water, there are fixed number of hydronium ions per unit volume of the solution.

On dilution number of hydronium ion per unit volume decreases and the concentration of hydronium ions $\left(H_3{O}^{+}\right)$ deceases and becomes weak.

In this way concentration of hydronium ion affects when a solution of acid is diluted.