Question

Which of the reactants act as an oxidant or reductant if any:
${{C}_{2}}{{H}_{4}}+B{{r}_{2}}\to {{C}_{2}}{{H}_{4}}B{{r}_{2}}$
A.$B{{r}_{2}}$ is oxidant
B.${{C}_{2}}{{H}_{4}}$ is reductant
C.Both of these
D.None of these

Answer 1

Before answering this question, we should know what is an oxidant and reductant. The oxidant is a substance that oxidizes the other chemical substance that is present in the reaction and it gets reduced. The reductant is a substance that reduces other chemical substances that is present in the reaction and it gets oxidized.

Complete answer:
Oxidant increases the oxidation state of the other substance and the oxidation state of itself will decrease whereas the reductant decreases the oxidation state of the other substance and the oxidation state of itself will increase.
${{C}_{2}}{{H}_{4}}+B{{r}_{2}}\to {{C}_{2}}{{H}_{4}}B{{r}_{2}}$
In this reaction,
The oxidation number of Carbon increases from -2 to -1. That means ${{C}_{2}}{{H}_{4}}$is oxidized and acts as a reductant.
The oxidation number of bromine decreases from 0 to -1. That means $B{{r}_{2}}$is reduced and acts as an oxidant.

So, option (C) Both of these is correct.

Note:
Difference between oxidation and reduction are:
The loss of electrons from an atom or a molecule is known as oxidation whereas the gain of electrons from an atom or a molecule is known as Reduction. In oxidation, the oxidation state increases whereas in reduction, the oxidation state decreases. The release of electrons in the surrounding is Oxidation whereas the electrons obtained from the surrounding is reduction. The increase in the positive charge of a chemical species is caused by oxidation whereas the increase in the negative charge of a chemical species is caused by reduction. Oxidation happens in reducing agents whereas reduction happens in oxidizing agents. The two half-reactions of redox reactions are oxidation and reduction.