by Standard: Zinc sulphate monohydrate contains not less than 99.0 per cent and not more than 101.0 per cent of ZnSO4, H2O.
Procedure: Dissolve 0.3 g in 5ml of dilute acetic acid into a 500ml conical flask and add 200 ml of water. Add about 500 mg of xylenol orange triturate and hexamine until the solution becomes violet – pink; add 2g of hexamine in excess. Titrate with 0.1M disodium edetate until the violet-pink colour changes to yellow.
1 ml of 0.1 M disodium edetate is equivalent to 0.01795 g (17.95 mg) of ZnSO4, H2O.
