Question

The hydrogen ion concentration in an acidic solution is ${10}^{-5}$. What is the pH value of the solution?

Answer 1

Step 1:

The pH is the measure of the concentration of hydrogen ions $\left({\mathrm{H}}^{+}\right)$ in a solution. It can be calculated by taking the log of the concentration of hydrogen ions. The higher the concentration of hydrogen ions, the lower will be the pH.

Step 2:

Hydrogen ion concentration = ${10}^{-5}$.

The pH can be calculated by the following formula:

$\begin{array}{rcl}\mathrm{pH}& =& -\log \left[{\mathrm{H}}^{+}\right]\end{array}$

Step 3:

The known value is substituted.

$\begin{array}{rcl}\mathrm{pH}& =& -\log {\left[\mathrm{H}\right]}^{+}\\ & =& -\log \left({10}^{-5}\right)\\ & =& 5\end{array}$

Hence, the pH of the solution = 5.