Zinc Oxide

Zinc Oxide IP



Description A soft, White or faintly yellowish white amorphous powder, free from grittiness, It gradually absorbs carbon dioxide from air. practically insoluble in water and in ethanol (95 %) It dissolves in dilute mineral acids.
Identification A. Becomes yellows when strongly heated. The yellow color disappears on cooling.
B.Dissolve 0.1 g in 1.5 ml of 2 M hydrochloric acid and dilute to 5 ml with water. The solution gives the reaction of zinc salts.
Alkalinity Shake 1.0 g with 10 ml of boiling water; add 0.1 ml of phenolphthalein solution and filter. If the filtrate is red not more than 0.3 ml of 0.1 M hydrochloric acid is require to discharge the color.
Carbonate and Substances Insoluble in acids Dissolve 1.0 gm in 15 ml of 2 M hydrochloric Acid.No.effervescence is produced and the solution is not more opalescent than opalescence standard OS2, Appendix 6.1, and colorless, Appendix 6.2.
Arsenic Dissolve 2 g in 15 ml of brominated hydrochloric acid AsT and 45 ml of water and remove the excess of bromine with a few drops of stannous chloride solution AsT The resultant solution complies with the limit test for arsenic Appendix 3.9 (5 PPM)
Iron Dissolve 0.1g in a mixture of 5 ml of water and 1 ml of hydrochloric acid and dilute to 40 ml with water. The resulting solution complies with the limit test for iron, Appendix 3.13 (200 PPM). Use 0.5 ml of thioglycollic acid in the test.
Lead Lead Dissolve 2g in a mixture of 20-ml water and 5 ml of glacial acetic acid and add 0.25 ml of potassium chromate solution; the solution remains clear.
Loss On Ignition Not more than 1.0 % determined on 2 g by igniting at 500 C, Appendix 8.7
Assay Dissolve 0.15 g in 10 ml of 2 M acetic acid and dilute to 50 ml with water. To the resulting solution add about 50 mg of xylenol orange triturate and sufficient hexamine and produce violet-pink color. Add a further2 g of hexamine and titrate with 0.1 M disodium edetate until the solution becomes yellow. Each ml of 0.1 M disodium edetate is equivalent to 0.008138g of ZnO. Zinc Oxide contains not less than 99.0 % & not more than 100.5 %

Reagents required :- phenopthalein solution