Zinc hydroxide is an inorganic chemical compound with formula Zn(OH)2. It occurs naturally in three rare minerals namely wulfingite, ashoverite and sweetite. It is an amphoteric hydroxide. Zinc hydroxide reacts with both bases and acids. It is an insoluble hydroxide which reacts with strong acid and gets dissolved.
Properties of Zinc Hydroxide
| Zn(OH)2 | Zinc hydroxide |
| Density | 3.05 g/cm³ |
| Molecular Weight/ Molar Mass | 99.424 g/mol |
| Melting Point | 125° C (257° F) |
| Chemical Formula | H2O2Zn |
Zinc Hydroxide Structure – Zn(OH)2
Physical Properties of Zinc Hydroxide – Zn(OH)2
| Odour | Odourless |
| Appearance | Dull white flocculent precipitate |
| Valency of Zn | 2 |
| pH | 8.88 |
| Oxidation state | +2 |
| Solubility | Slightly soluble in water, insoluble in alcohol |
Chemical Properties of Zinc Hydroxide – Zn(OH)2
- Aluminium reacts with zinc hydroxide solution gives a white precipitate which is soluble in excess of the reagent to form complex Al(OH)4 indicates the presence of aluminium.
2Al3+(aq) + 3Zn(OH)2(aq) → 2Al(OH)3(s) + 3Zn
- Zinc cations react with hydrogen sulphide in the presence of ammonia and ammonium chloride form a white precipitate of zinc sulphide which is soluble in acids.
Uses of Zinc Hydroxide – Zn(OH)2
- Used in medicine as an adsorbing agent.
- Utilised for careful dressings where it works as a retentive. Huge bandages that are utilised post-medical procedure are covered with the zinc compound for engrossing the blood from the injury.
- Used as an intermediate for commercial production of pesticides and pigments.