In this experiment, pH measurements of two solutions are HCl and NaOH by using pH meter. pH meter can know electrical potential and pH value from solution at 25°C. pH value is the degree of the acid or alkaline condition in the solution. The hydrogen ion is measured in order to determine the hydrogen ion activity. The pH ranges from 0 to 14.At neutral pH (pH 7), the basic pH (pH>7) and the acid pH (pH