Effect of citric acid concentration on its dissociated and non-dissociated forms

The authors have studied the acid-base properties of citric acid by potentiometric titration at a temperature of 298 K and concentrations of CH3Cit(OH) of 0.01 and 0.02 mol/L. The results of potentiometric titration depend on the concentration of substances and the time of setting the equilibrium pH value of the titrated solution. The potentiometric method determined three carboxyl groups of citric acid corresponding to pKa1, pKa2, and pKa3. The values of citric acid dissociation constants for 0.02 mol/L concentration are 2.75, 4.45, and 5.82. The authors constructed the distribution diagrams of dissociated forms for both studied concentrations of citric acid. According to the data obtained, the distribution curves shift to the right on the pH scale with increasing acid concentration.