pH (potential of hydrogen) scale is defined as the way to measure how acidic or basic a solution is, this range will gro from 0 to 14, and 7 means that the solution is neutral. This scale is measured by observing how much H+ ions and OH- ions are in the solution.
In order to calculate the pH, we need the concentration of H+ or OH-, and then we can use the following formula with a logarithm
pH = -log [H+], the brackets indicate concentration
Acidic solutions must have their pH below 7
Basic solutions must have their pH above 7
Neutral solutions will have the pH at exactly 7