Titration of NaOH solution vs. potassium hydrogen phthalate: an interactive lab experiment.

Abstract

Since NaOH is not a primary standard, its solution must be titrated (standardized) against potassium hydrogen phthalate (KHP). This is an interactive simulation of a near 0.1 M NaOH solution. The experiment begins with the primary standard weighing. Then the KHP mass is dissolved in a flask, 1-2 drops of indicator (phenolphtalein) added and finally neutralized to phenolphtalein endpoint adding the alkali solution from the burette. The experiment can be repeated as may times as desired. After each titration, a page allows calculation of the alkali molarity. Data are saved and displayed later on a table which also shows the average molarity. The protocol must be followed strictly in order to go to the end of titration. No relevant operation can be skipped. The exercise includes a puzzle-like equation for calculation and a true-false autocorrectable test.