To determine the pH of given samples using
(1) universal indicator
(2) pH paper, and
(3) digital pH meter.
pH value of water indicates the hydrogen ion concentration in water and concept of pH was put forward by
Sorenson (1909). pH is expressed as the logarithm of the reciprocal of the hydrogen ion concentration in moles/
litre at a given temperature. The pH scale extends from 0 (very acidic) to 14 (very alkaline) with 7 corresponding
to exact neutrality at 25°C. pH is used in the calculation of carbonate, bicarbonate and CO2, corrosion and stability
index etc. While the alkalinity or acidity measures the total resistance to the pH change or buffering capacity, the
pH gives the hydrogen ion activity. pH can be measured colorimetrically or electrometrically.