The document describes an experiment to determine the water of crystallization in Mohr's salt, (NH4)2Fe(SO4)2.XH2O, by titrating a solution of the salt with standardized potassium manganate(VII). The experiment involves standardizing the KMnO4 solution using sodium oxalate, then titrating samples of Mohr's salt solution and calculating the iron content. Based on comparing the experimental iron percentage to theoretical percentages for different values of X, the water of crystallization is determined to be 6 moles, giving the formula (NH4)2Fe(SO4)2.6H2O.