Physical properties of Zinc Oxide
Appearance and Properties: White powder or hexagonal crystals. Odorless and tasteless, no sand. It turns yellow when heated, then becomes white again after cooling, and sublimates when heated to 1800 C. The covering force is half of the titanium dioxide and zinc sulfide. The coloring force is 2 times that of the alkaline lead carbonate.
Solubility: Soluble in acid, concentrated alkali hydroxide, ammonia and ammonium salt solution, insoluble in water, ethanol.
Zinc oxide is a famous white pigment, commonly known as zinc white. Its advantage is that H2S gas does not blacken, because ZnS is also white. When heated, ZnO is gradually changed from white and light yellow to lemon yellow. When it is cooled, the yellow will be removed. Using this feature, it is added into the paint or added to the thermometer to make color paint or color change thermometer. Because of its astringency and certain bactericidal ability, ZnO is often used as ointment in medicine and as catalyst.
Chemical reaction formula:
Reaction to NaOH: ZnO+2NaOH+H2O=Na2[Zn (OH)