Chemical Name: ALUMINUM SULFATE? ????????????RM Control No.:__________

PARAMETERS

USP 25

STANDARD

RESULT

REMARKS

Description

White, crystalline powder, shining plates, or crystalline fragments. Is stable in air. Is odourless, and has a sweet taste, becoming mildly astringent.

Solubility

Freely soluble in water; insoluble in alcohol.

pH

A 1 in 20 solution has?pH of not less than 2.9

Identification

A 1 in 10 solution responds to tests for;

Aluminum- Solutions of aluminum salts yield with 6N ammonium hydroxide a gelatinous, white precipitate that is insoluble in an excess of 6N ammonium hydroxide. 1N sodium hydroxide or sodium sulfide TS produces the same precipitate, which dissolves in an excess of either of these reagents.

Sulfate-Solutions of sulfates yield with barium chloride TS a white precipitate, which is insoluble in hydrochloric acid and in nitric acid. Hydrochloric acid produces no precipitate when added to solutions of sulfates.

Assay

Accurately weigh 7.5g into a 250mL vol. Flask and fill to volume with water.?Pipet 10mL of solution into a 250mL beaker, add 25mL 0.05M EDTA, 20mL acetic acid-ammonium acetate buffer TS.?Heat solution to near boiling for 5 minutes.?Cool, add 50mL alcohol, 2mL dithizone TS.?Titrate with 0.05M zinc sulfate VS to a rose-pink color.p.90.