Determination of the End Point
Determination of the End Point The end point in the non-aqueous titrations is determined by the following two methods: 1. Potentiometric method: In this method, the end point is determined by using the indicator electrode and reference electrode. Generally, glass electrode is used as the indicator electrode and saturated calomel electrode (SCE) is used as the reference electrode. 2. Indicator method: Indicators used in the non-aqueous titrations are as follows: ➢ Crystal violet: It is used as 0.5% w/v solution in glacial acetic acid. It shows the end point by changing the color from violet to blue followed by green then to greenish yellow. ➢ Methyl red: It is used as 0.2% w/v solution in dioxane and changes the color from yellow to red. ➢ Naphthol benzein: It is used as 0.2% w/v solution in ethanoic acid and shows the colour changes from yellow to green color. ➢ Quinaldein red: It is used as indicator for most of the drug determinations in dimethylformamide and shows the