Question

what happens when
Aluminium is treated with H2 S o4 concentrated​

Answer 1

Explanation:

=>Aluminium reacts with hot, concentrated sulphuric acid to form aluminium sulphate with the evolution of sulphur dioxide gas. Sulphuric acid acts an oxidising agent, and gets itself reduced to SO2.

Only with the dilute acid, the metal liberates hydrogen gas.

Answer 2

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 are what is known as an ox­i­da­tion-re­duc­tion re­ac­tion or redox reaction. Both oxidation and reduction take place simultaneously.

Reactions involved,

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↑

Net-ion­ic form:

2Al⁰ + 6H⁺ → 2Al³⁺ + 3H₂↑

Balanced equation,

In molec­u­lar form, the re­ac­tion looks as fol­lows:

2Al + 6HCl → 2Al­Cl₃ + 3H₂↑.