Determination of acids (citric and acetic acids)
(1) Citric acid
Dissolve a known volume or weight of sample in a known volume of distilled water. From this, take an aliquot and titrate with 0.1 N NaOH using phenol-phthalein as an indicator. The endpoint is denoted by the appearance of pink colour.
(2) Acetic Acid
Dilute 10 ml of sample with water in a porcelain dish (about 5 inches in diameter), add phenolphthalein as an indicator, and titrate with 0.5 N NaOH.
Titrate X Normality of alkali X meq wt. of acid* X 100
% Acid = ——————————————————————————
Wt. or volume of sample
*Note: Meq = Millequivlent
Meq wt. of citric acid = 0.06404
Meq wt. of ascorbic acid = 0.06005