pH of a solution generally means the measurement of concentration of Hydrogen ion (H+) in an aqueous solution. The value of pH has the minimum range of 0 and maximum range of 14. Range 7 is the neutral. Below pH7, the solution shows acidic properties in nature whereas, above pH 7, the solution shows base properties in nature. To determine the pH value in an acqueous solution, the following formula is used :- 

pH = - log [H3O+].