Question

"(Mg + Cl₂ = MgCl₂is redox reaction)".
How is it a redox reaction if it doesn'tinvolve any reaction of oxygen and hydrogen ?

Answer 1

Mg + 2HCl---> MgCl2 + H2

This is a single replacement reaction.

Mg is oxidized to MgCl2 (+2)

2H is reduced to H2 (0)

Magnesium is oxidized from 0 in Mg to Mg2+ in its oxidation state in MgCl2.

Hydrogen is reduced from +1 in HCl to 0 in its oxidation state in H2.

So both oxidation and reduction occur simultaneously, making these as redox reactions.