In which of the following solution the concentration of ${\text{H}}^{+}$ ion is the maximum?

The $\text{pH}$ of a solution is inversely related to its hydrogen ion (${\text{H}}^{+}$) concentration. Mathematically, it is defined as:
$$\text{pH}=-{\log }_{10}[{\text{H}}^{+}]$$
$$[{\text{H}}^{+}]=10^{-\text{pH}}\text{mol/L}$$
Comparing the choices:For $\text{pH}=5$: $[{\text{H}}^{+}]=10^{-5}\text{mol/L}$ For $\text{pH}=6$: $[{\text{H}}^{+}]=10^{-6}\text{mol/L}$ For $\text{pH}=8$: $[{\text{H}}^{+}]=10^{-8}\text{mol/L}$ For $\text{pH}=9$: $[{\text{H}}^{+}]=10^{-9}\text{mol/L}$ Since $10^{-5}>10^{-6}>10^{-8}>10^{-9}$, the solution with a $\text{pH}$ of $5$ has the maximum concentration of ${\text{H}}^{+}$ ions. Lower $\text{pH}$ indicates a stronger acidic nature and higher ${\text{H}}^{+}$ concentration.