The pH of a solution indicates how acid or alkaline the solution is. A pH of less than 7 indicates that it is an acid, and a pH of more than 7 indicates that it is an alkali.
1. (chemistry) p(otential of) H(ydrogen); the logarithm of the reciprocal of hydrogen-ion concentration in gram atoms per liter; provides a measure on a scale from 0 to 14 of the acidity or alkalinity of a solution (where 7 is neutral and greater than 7 is