The equation gives show that one mole of –OCH3 gives 1 mole of Agl . Hence, by weighing Agl, we can calculate the number of OCH3 groups in the given compoumd. This is the principle of Ziesel’s method. (Zerwittenoff method is for estimation of active hydrogen using of Grignard reagent) Zeisel’s method is a method of determining the number of methoxy (–OCH3) groups in an organic compound. The compound is heated with excess hydriodic acid, forming an alcohol and iodomethane : R−O−CH3+HI → ROH+CH3I The iodomethane is distilled off and led into an alcoholic solution of silver nitrate, where it precipitates silver