Question

What happens in a reduction half-reaction?

Answer 1

The answer is elements gain electrons. Oxidation reduction is elements lose electrons. And oxygen is added/lost can be a type of oxidation/reduction reaction.

Answer 2

Answer: Option (a) is the correct answer.

Explanation:

A reduction-half reaction is defined as the reaction in which there occurs gain of one or more number of electrons by a specie or element.

Or, in a reduction-half reaction there occurs loss of oxygen if it is present in a reaction.

But in a reduction-half reaction loss of electrons will always take place.

For example, $CuO + Mg \rightarrow Cu + MgO$

Reduction-half reaction: $Cu^{2+} + 2e^{-} \rightarrow Cu$

So here, oxidation state of copper is changing from +2 to 0. Also, loss of oxygen is occurring in the reaction equation.

Oxidation-half reaction: $Mg \rightarrow Mg^{2+} + 2e^{-}$

Thus, we can conclude that in a reduction half-reaction elements gain electrons.