How does aluminum react with water?
Aluminum metal will readily react with water at room temperature to form aluminum hydroxide and hydrogen. That reaction doesn't typically take place because a layer of aluminum oxide naturally coats the raw metal, preventing it from coming directly into contact with water.
When the aluminium is in its passive pH zone, corrosion tends to occur as pitting or localised corrosion. Corrosion takes place where the oxide layer is breached or under a deposit and is mainly caused by chlorides. Aluminium is extremely corrosion-resistant in very pure water.
Aluminum metal rapidly develops a thin layer of aluminum oxide of a few millimeters that prevents the metal from reacting with water. When this layer is corroded a reaction develops, releasing highly flammable hydrogen gas.
Aluminium is unusual, because it is a reactive metal that does not react with water. Its surface forms a protective layer of aluminium oxide that keeps water away from the metal below. The apparatus used to react a metal with steam and collect the gas produced is shown below.
This is because aluminium reacts with oxygen present in air to form a thin layer of aluminium oxide on its surface. This oxide layer is very stable and acts as a protective coating by preventing further reaction of aluminium. Also, it is light in weight and a good conductor of heat.
Water and soil
Most aluminum-containing compounds do not dissolve to a large extent in water unless the water is acidic or very alkaline.
Aluminium does not react with pure water but when salts are present in water they remove the oxide layer on the surface making aluminium reactive. Then aluminium reacts with water slowly . So aluminium vessels should not be kept in water overnight.
Aluminium does not react very well with the oxygen in the air but it is in fact quite a reactive metal. The reason it does not react is that is has already reacted, but the aluminium oxide has formed in a thin, tightly bonded layer that protects the aluminium foil from further attack.
Copper and Gold do not react with water, because they lie below hydrogen in the reactivity series.
Metals like aluminium, iron and zinc do not react either with cold or hot water.
Why is aluminum metal not affected by air and water?
Aluminum does not appear to react with water because an outer layer of aluminum oxide (Al2O3) solid forms and protects the rest of the metal.
Aluminium metal reacts vigorously with all the halogens to form aluminium halides. So, it reacts with chlorine, Cl2, bromine, I2, and iodine, I2, to form respectively aluminium(III) chloride, AlCl3, aluminium(III) bromide, AlBr3, and aluminium(III) iodide, AlI3.
(iv) Hot water has no action on aluminium.
Exposure to aluminum is usually not harmful, but exposure to high levels can affect your health. Workers who breathe large amounts of aluminum dusts can have lung problems, such as coughing or abnormal chest X-rays.
Aluminum reacts with steam to form an aluminum oxide with the evolution of hydrogen gas.
Metals like aluminium, iron and zinc do not react either with cold or hot water. Metals such as lead, copper, silver and gold do not react with water at all.