Question

Why is the burning of carbon with oxygen considered an oxidation-reduction reaction?

(i)Write the chemical equation for this reaction.

(ii) Identify the substance: (a) getting oxidised (b) getting reduced (c) Oxidising agent (d) Reduced agent

Answer 1

Carbon, when burned in presence of oxygen, is a combustion reaction.

The chemical equation can be written as,

$$\begin{gathered} \mathrm{C}\left(\mathrm{s}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right)\to {\mathrm{CO}}_2\left(\mathrm{g}\right) \\ 00+4-4 \\ \mathrm{Carbon}\mathrm{oxygen}\mathrm{carbondioxide} \end{gathered}$$

1. Oxidation can be said as loss of electrons and reduction can be said to be the gaining of electrons.
2. As the oxidation state of carbon is increasing from 0 to +4, showing it loses electrons and the oxidation state of oxygen is decreasing from 0 to -4, showing it gained electrons.
3. Hence, the burning of carbon with oxygen is considered an oxidation-reduction reaction.
4. Oxidizing agents are those chemical species that can remove electrons from other species and Reducing agents are those chemical species that can add electrons to other species.
5. Here, the oxidation state of carbon is increasing from 0 to +4 showing it loses electrons and the oxidation state of oxygen is decreasing from 0 to -4 showing it gained electrons.
6. Hence, (a) Carbon is oxidized. (b) Oxygen is reduced. (c) Oxygen is the oxidizing agent. (d) Carbon is the reducing agent.