These economical drop
count procedures provide a low-cost method for titrametric
determinations. To calculate concentration, simply add an indicator to
the sample, then use the dropper to add titrant until the color changes.
One drop is equivalent to 10 ppm ie: 5 drops would equal 50 ppm Cl
(5x10). Typical accuracy is +/- 1 drop for titrations requiring up to
20 drops and +/- 5% for titrations over 20 drops. Most titrations
require 10-20 drops.