Question

The oxide which cannot act as a reducing agent is?
Options-
A.$$S{O}_2$$
B.$$N{O}_2$$
C.$$C{O}_2$$
D.$$Cl{O}_2$$

Answer 1

Hint: The ability to act as a reducing agent is associated with the tendency of the chemical entity to itself get oxidized and facilitate the process of reduction of another reactant available in the reaction mixture. Thus, a redox reaction is said to take place when a reducing agent acts on a substance.

Complete answer:
The process of oxidation is defined as the process involving loss of electrons, gain of oxygen atoms or an enhancement in the oxidation state of the central atom. Reduction is the complete opposite of the oxidation process.
For any oxide to act as a reducing agent, it should itself have a tendency to get oxidized and then reduce another chemical species. Thus, an oxide that acts as a reducing agent must have enough electron density to lose electrons and its central atom should be able to extend its oxidation state.
Sulphur can accommodate a maximum oxidation state of $$+6$$ therefore its dioxide can further be oxidized into a trioxide or any oxoacid.
Nitrogen can show a maximum oxidation state of $$+5$$ and its dioxide can further form an oxoacid like nitric acid.
Chlorine being a member of the seventeenth group of the periodic table can extend its oxidation state upto $$+7$$ and is therefore a good reducing agent.
Carbon can only have a maximum oxidation state of $$+4$$ which is already present in its oxide.

$$\Rightarrow$$ Thus, carbon dioxide cannot be oxidized further to act as a reducing agent and option (C) is correct.

Note:
Carbon is the first member of the fourteenth group and has only four electrons in its outermost shell. Thus, its maximum oxidation state is $$+4$$ also the absence of vacant d-orbitals on carbon does not allow it to extend its oxidation state further.