Each unit change in pH represents a change in activity of H⁺ or OH ions by

Solution (By Examveda Team)

pH is a measure of the acidity or basicity of any substance. It ranges from 0 - 14, 7 is neutral while a pH value of 0 - 7 indicates acidity whereas a Value greater than 7 indicates the Basicity of any substance.
It is a measure of the relative amount of free hydrogen and hydroxyl ions in the liquid. A change of one pH unit corresponds to a ten times change in Hydrogen ion concentration.