Count each drop. Continue adding drops until a light pink color persists for 30 seconds. Repeat for other two samples. In order to accomplish this, you must determine alkalinity from the following procedure. The alkalinity of water is its quantitative capacity to neutralize a strong acid to a designated pH. Alkalinity is a measure of a gross property of water and can be interpreted in terms of specific substances only when the chemical composition of the sample is known.
Alkalinity is primarily a function of carbonate, bicarbonate and hydroxide content of the water.
Pour the contents of the tube into the square mixing bottle. Add the contents of one phenolphthalein indicator powder pillow to the mixing bottle. Swirl to mix. If the water remains colorless, the phenolphthalein alkalinity is zero. In this case proceed to Step 7.