Alkalinity measurements by acid-base titration method.
Pipet 10ml of sample into flask. Add 2 drops of phenolphthalein- indicator. If the sample turns pink, CO3” ions are present (pH≥8.3). Titrate rapidly under continues shaking until this colour disappears, note the amount of acid used (xml). Now add 2 drops of methyl orange and continue titration until yellow turns to salmon pink (total acid used=yml).
Image is attached for calculation and conversion to ppm.