Question

In this reaction, C acts as a/an:
${\text{ZnO + C}} \to {\text{Zn + CO}}$.
A.Oxidising agent
B.Reducing agent
C.Dehydrating agent
D.Hydrating agent

Answer 1

Hint:The process of losing electrons and gaining oxygen is called “oxidation”, while the process of gaining electrons and gaining hydrogen is called “reduction”. The elimination of water molecules is dehydration, while the addition of water is hydration.

Complete step by step answer:
An oxidising agent is one that oxidises another chemical entity to get reduced itself while a reducing agent is one that reduces another chemical entity or loses electrons itself. In the above reaction, the oxidation state of zinc in zinc oxide is $\left( { + 2} \right)$ to balance the oxidation state of oxygen which is $\left( { - 2} \right)$. Any element in its natural form has 0 oxidation number. Hence both carbon and zinc have 0 oxidation number. Hence the oxidation number of zinc is reduced from $\left( { + 2} \right)$ to zero in the reaction, so we can say that zinc has been reduced, while the oxidation number of carbon has increased from 0 to $\left( { + 2} \right)$ in carbon monoxide, hence it has been oxidized.
So, here carbon gets oxidised itself and hence, it is the reducing agent.

Hence, the correct answer to the above question is option B.

Note:
Carbon is used as a reducing agent in different reactions. It is mainly used as the reducing agent in the extraction of different metals. Even carbon monoxide is also used as the reducing agent in different reactions due to the fact that it reduces different metal oxides at high temperatures into the respective metals.