The pH of a solution is the negative logarithm of the hydrogen ion concentration.
Acidic solutions have pH below 7.
Basic solutions have pH values above 7.
pOH is simply the power of hydroxide ion concentration and is figured the same way as pH but using the concentration of hydroxide ion instead.
pH is calculated using the following formula:
pH = -log[H+]
pOH is calculated using the following formula:
pOH = -log[OH-]
