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Zinc nitrate is usually prepared by dissolving zinc metal, zinc oxide, or related materials in nitric acid: Zn + 2 HNO 3 → Zn(NO 3) 2 + H 2 ZnO + 2 HNO 3 → Zn(NO 3) 2 + H 2 O. These reactions are accompanied by the hydration of the zinc nitrate. The anhydrous salt arises by the reaction of anhydrous zinc chloride with nitrogen dioxide: [1]
The resulting acid solution is the 68.5% azeotrope, and can be further concentrated (as in industry) with either sulfuric acid or magnesium nitrate. [ 36 ] Alternatively, thermal decomposition of copper(II) nitrate gives nitrogen dioxide and oxygen gases; these are then passed through water or hydrogen peroxide [ 38 ] as in the Ostwald process:
Zinc is a strong reducing agent with a standard redox potential of −0.76 V. Pure zinc tarnishes rapidly in air, rapidly forming a passive layer. The composition of this layer can be complex, but one constituent is probably basic zinc carbonate, Zn 5 (OH) 6 CO 3. [8] The reaction of zinc with water is slowed by this passive layer.
The reaction with hydrochloric acid is an equilibrium reaction that favors formation of tetrachloroaurate(III) anions. This results in a removal of gold ions from solution and allows further oxidation of gold to take place. The gold dissolves to become chloroauric acid. In addition, gold may be dissolved by the chlorine present in aqua regia.
Strong acids, such as hydrochloric or sulfuric acid, can remove the passivating layer and the subsequent reaction with the acid releases hydrogen gas. [51] Zinc chemistry resembles that of the late first-row transition metals, nickel and copper, [53] as well as certain main group elements.
The reaction is effected with zinc. The key zinc-intermediate formed is a carbenoid (iodomethyl)zinc iodide which reacts with alkenes to afford the cyclopropanated product. The rate of forming the active zinc species is increased via ultrasonication since the initial reaction occurs at the surface of the metal.
This is achieved in practice through a process called double leaching. The calcine is first leached in a neutral or slightly acidic solution (of sulfuric acid) in order to leach the zinc out of the zinc oxide. The remaining calcine is then leached in strong sulfuric acid to leach the rest of the zinc out of the zinc oxide and zinc ferrite.
Schultze reagent (also known as Chlor-Zinc-Iodine Solution) [1] is an oxidizing mixture consisting of a saturated aqueous solution of potassium chlorate KClO 3 and varying amounts of concentrated nitric acid HNO 3. It is commonly used in palynologic macerations. It was invented by Max Schultze.