Transfer approximately 30 mL of water to a 50-mL
glass-stoppered weighing bottle, stopper, and weigh to the
nearest 0.1 mg. Rapidly add a convenient size sample, depending
upon the acid strength as given in Table 1, stopper
immediately, and reweigh. Transfer the sample to a 400-mL
beaker containing approximately 50 mL of water and add 3 to
5 drops of phenolphthalein indicator solution.