Add 4 drops of phenolphthalein indicator to 50 or 100 cc. of the sample
in a white porcelain casserole or an Erlenmeyer flask over a white
surface. If the solution becomes colored, hydroxide or normal carbonate
is present. Add N/50 sulfuric acid from a burette until the coloration
disappears.
The phenolphthalein alkalinity in parts per million of calcium carbonate
is equal to the number of cubic centimeters of N/50 sulfuric acid used
multiplied by 20 if 50 cc. of the sample was used, or by 10 if 100 cc.
was used.