pH is scale which measures the acidity or alkalinity of a solution. It ranges from a level of 1 to 14. A pH which range from 1 to 6 represents an acidic substance. At pH of 7, signifies the solution is neutral. And at a pH of 8-14 represents a basic solution. pH is expressed as the negative logarithm of the concentration of hydronium ions.
pH = - log [H+]
pH = - log 1
pH = 0