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Aluminium oxide is an amphoteric substance, meaning it can react with both acids and bases, such as hydrofluoric acid and sodium hydroxide, acting as an acid with a base and a base with an acid, neutralising the other and producing a salt. Al 2 O 3 + 6 HF → 2 AlF 3 + 3 H 2 O Al 2 O 3 + 2 NaOH + 3 H 2 O → 2 NaAl(OH) 4 (sodium aluminate)
Sodium aluminate is also formed by the action of sodium hydroxide on elemental aluminium which is an amphoteric metal. The reaction is highly exothermic once established and is accompanied by the rapid evolution of hydrogen gas. The reaction is sometimes written as: 2Al + 2NaOH + 2H 2 O → 2NaAlO 2 + 3H 2
Similarly to the nucleophilic carbon center in the carbene, the lone pair on the aluminium center binds to the first azide equivalent. Nitrogen gas is liberated. With the second equivalent of azide, a five-member ring is formed. Aluminium (I) systems undergo reactions with azides in the same fashion as carbenes. [10]
Aluminium has a high chemical affinity to oxygen, which renders it suitable for use as a reducing agent in the thermite reaction. A fine powder of aluminium reacts explosively on contact with liquid oxygen; under normal conditions, however, aluminium forms a thin oxide layer that protects the metal from further corrosion by oxygen, water, or ...
An excess of oxygen gives oxides of nitrogen, including nitrogen monoxide and nitrogen dioxide: N 2 H 4 + 2 O 2 → 2 NO + 2 H 2 O N 2 H 4 + 3 O 2 → 2 NO 2 + 2 H 2 O. The heat of combustion of hydrazine in oxygen (air) is 19.41 MJ/kg (8345 BTU/lb). [57] Hydrazine is a convenient reductant because the by-products are typically nitrogen gas and ...
Aluminium has a high chemical affinity to oxygen, which renders it suitable for use as a reducing agent in the thermite reaction. A fine powder of aluminium reacts explosively on contact with liquid oxygen; under normal conditions, however, aluminium forms a thin oxide layer (~5 nm at room temperature) [43] that protects the metal from further ...
Aluminium nitrate may instead be prepared by the reaction of nitric acid with aluminium(III) chloride. Nitrosyl chloride is produced as a by-product; it bubbles out of the solution as a gas. More conveniently, the salt can be made by reacting nitric acid with aluminium hydroxide .
Carbonic acid is an illustrative example of the Lewis acidity of an acidic oxide. CO 2 + 2OH − ⇌ HCO 3 − + OH − ⇌ CO 3 2− + H 2 O. This property is a key reason for keeping alkali chemicals well sealed from the atmosphere, as long-term exposure to carbon dioxide in the air can degrade the material.