Aluminum reacts with diluted hydrochloric acid at room temperature. The metal aluminium dissolves in hydrochloric acid, producing aluminum chloride and colorless hydrogen gas. The reaction taking place between aluminium and hydrochloric acid is irreversible. And the final products will not react with each other.
Type of reaction
The reaction between metallic aluminum and hydrochloric acid is what is known as an oxidation-reduction reaction or redox reaction. Both oxidation and reduction take place simultaneously.
Listed below are the stepwise reaction taking place in between aluminium and hydrochloric acid
Step 1: Aluminum acts as the reducing agent, giving up electrons:
Al⁰ – 3e → Al³⁺
Step 2: Cations of hydrochloric acid take these electrons and are reduced to molecular hydrogen:
2H⁺ + 2e → H₂↑
The complete ionic reaction equation is as follows:
2Al⁰ + 6H⁺ + 6Cl⁻ → 2Al³⁺ + 6Cl⁻ + 3H₂↑
2Al⁰ + 6H⁺ → 2Al³⁺ + 3H₂↑
In molecular form, the reaction looks as follows:
2Al + 6HCl → 2AlCl₃ + 3H₂↑