Question

H2 + Cl2 ----> 2HCl . prove that this is a redox reaction

Answer 1

Cl2 + H2 = 2HCl


In this redox reaction,

H atoms in H2 are oxidized, Cl atoms in Cl2 are reduced, Cl2 is the oxidizing agent, and 

H2 is the reducing agent

Answer 2

Anything that involves change of oxidation states of reactants in the products or exchange of electrons can be considered a redox reaction.

Here, H2 (oxidation state = 0) changes to H+ (oxidation state = +1) and Cl2 (oxidation state = 0) changes to Cl− (oxidation state = -1)

So, H2 has been oxidised and Cl2 has been reduced, making this a redox reaction.