Question

Assertion: In the reaction,
$2C{{u}_{2}}O(s)\,+C{{u}_{2}}S(s)\to 6Cu(s)+S{{O}_{2}}(g)$
Copper acts as a reductant and sulphur act as an oxidant
Reason: The given reaction is not a redox reaction.
A.Both assertion and reason are correct and reason is the correct explanation for assertion.
B.Both assertion and reason are correct and the reason is not the correct explanation for assertion.
C.The assertion is correct but the reason is incorrect.
D.Both assertion and reason are incorrect.

Answer 1

Hint: Before solving this question, we should first know about the Redox Reactions then we will be able to learn how to balance them. Reduction/Oxidation reactions also known as Redox reactions are the reactions in which one of the reactants is getting oxidized and another one is getting reduced.

Complete answer:
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 are present in the reaction and it gets oxidized.
The oxidation states are:
$2C{{u}^{+1}}_{2}{{O}^{-2}}(s)\,+C{{u}^{+1}}_{2}{{S}^{-2}}(s)\to 6C{{u}^{0}}(s)+{{S}^{+4}}{{O}^{-2}}_{2}(g)$
The copper is reduced from +1 state to zero. The oxidation state of the sulphur is getting oxidized from -2 state to -4. To increase the oxidation number of $C{{u}_{2}}S$ $C{{u}_{2}}O$ helps sulphur. Therefore, Cu(I) is an oxidant and sulphur of$C{{u}_{2}}S$ helps copper both in $C{{u}_{2}}S$ and $C{{u}_{2}}O$ to decrease its oxidation state. Therefore, S of $C{{u}_{2}}S$is a reductant. So, the reaction is redox.

So, Option (D) is correct- Both assertion and reason are incorrect.

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.