MT 31 - Free acidity or alkalinity

Content Handbook F


Outline of method

The acidity or alkalinity is determined by titration with standard acid or alkali, in the presence of methyl red. Where this is impracticable, the end point is determined electrometrically.

31.1 Methyl red indicator method

31.2 Electrometric procedure



The method is suitable for determining free acidity or alkalinity in technical or formulated pesticides. It does not allow the etermination of acids or alkalis which are insoluble in acetone-water mixtures.