Question

Answer the following reactions with respect to reaction of aluminium with steam:
1. Name the gas released when aluminium reacts with steam.
2. Why does the reaction stop after sometime ?
3. Why does the reaction continue at high temperature ?
4. Give the reaction of aluminium with water.?

Answer 1

Dear Student,

1. Hydrogen gas is liberated when Aluminium reacts with steam.
$2Al+3H_{2}O\to A{l}_2{O}_3+3H_2$
2. When reaction proceeds with steam at high temperature, it slows down and finally stops due to the presence of a coherent and adherent layer of aluminium oxide which forms on the surface of aluminium particles that prevents steam from coming into direct contact with the aluminium metal for further reaction.
3. Under high temperature conditions, due to corrosion of aluminium metal the outer layer dissolves in water i.e., the outer surface of this oxide is first hydrolyzed and then dissolves to yield soluble species which either remain in solution or, at intermediate values of pH, precipitate as a porous hydroxide of extremely small particle size. This is why at high temperature the reaction continues.
4. Aluminium generally doesn't react water, but slowly when conditions change or temperature rises, it reacts to form hydroxide and then oxide as follows:
2Al + 3H₂O → 3H_{​​​​​2} + Al₂O₃

Regards.