Fe2(SO4)3xH2O (anhydrous) 399.88
Ferric persulfate.
Ferric sesquisulfate.
Ferric tersulfate [10028-22-5].
Hydrate [142906-29-4].
Ferric Sulfate is hydrated Fe2(SO4)3. It contains not less than 73.0 percent and not more than 80.0 percent of Fe2(SO4)3.
Identification: Dissolve 0.5 g in a mixture of 50 mL of water and 3 mL of hydrochloric acid: this solution meets the requirements for the Ferric Salts test under Iron.
Limit of insoluble matter: Transfer 10 g in a covered beaker, and dissolve in a mixture of 100 mL of water and 5 mL of sulfuric acid. Heat to boiling, and warm on a steam bath for 1 hour. Filter the hot solution through a tared sintered-glass crucible of fine porosity. Wash the beaker and the filter with hot water, dry the crucible at 105 , cool in a desiccator, and weigh: not more than 2 mg of insoluble matter is found (0.02%).
Limit of chloride: 0.002%.
Limit of ferrous iron: Dissolve 4 g by warming with 50 mL of dilute sulfuric acid (1 in 10), cool, and titrate with 0.1 N potassium permanganate: not more than 0.16 mL is required to produce a permanent pink color (0.02% as Fe++).
Limit of copper: 0.005%.
Limit of zinc: 0.01%.
Limit of nitrate: 0.01%.
Substances not precipitated by ammonia: 0.1%.
