Question

Which of the following is a non reducing agent?
A.$S{O_2}$
B.${H_2}{O_2}$
C.$C{O_2}$
D.$N{O_2}$

Answer 1

Hint: We have to know that a reducing agent is the one which loses an electron or is donated to an oxidizing agent, whereas an oxidizing agent is the one which gains an electron or accepts an electron. A non-reducing agent is nothing but an oxidizing agent.

Complete answer:
We will look at all the options in brief:
Option A) this is an incorrect option as in the question it is asked for non reducing agents. But sulfur dioxide is a reducing agent. As in case of sulfur there is an empty d orbital thus oxidation state can vary from $ + 4$ to $ + 6$ making this a reducing agent.
Option B) this is an incorrect option as hydrogen peroxide is a reducing agent as when its oxidation state increases it behaves as a reducing agent but it can also act as an oxidizing agent.
Option C) this is a correct option as carbon dioxide cannot expand its oxidation state from $ + 4$ thus it cannot undergo oxidation thus it cannot act as a reducing agent. Thus this option is correct as it was asked for a non-reducing agent.
Option D) this is also a correct option as nitrogen dioxide can also act as oxidizing agent as on heating it decomposes itself into nitrogen and oxygen. Infact oxides of nitrogen almost behave as oxidizing agents.

Note:
We can infer that an oxidizing agent is the one that cannot expand its oxidation state up to certain values whereas in case of reducing agent the oxidation state increases from a number to lower value to higher value. Also we can look at strong reducing agents as the one that have low value of reduction standard potential.