Question

What is the oxidation number of carbon in ${\mathrm{C}}_2{\mathrm{O}}_4^{-2}$?

Answer 1

Oxidation number:

• It represents the number of electrons lost or gained by the atoms of an element in a compound.
• It is usually written with the sign $(+)$ and $(-)$ first and then the magnitude.

Determine the oxidation number of carbon in ${\mathbf{C}}_{\mathbf{2}}{\mathbf{O}}_{\mathbf{4}}^{\mathbf{-}\mathbf{2}}$:

• The oxidation state of oxygen is $(-2)$.
• The oxidation state of carbon will be:

$$\begin{gathered} 2\mathrm{x}+4(-2)=-2 \\ 2\mathrm{x}-8=-2 \\ 2\mathrm{x}=-2+8 \\ 2\mathrm{x}=+6 \\ \mathrm{x}=+3 \end{gathered}$$

Hence, the oxidation number of carbon in ${\mathbf{C}}_{\mathbf{2}}{\mathbf{O}}_{\mathbf{4}}^{\mathbf{-}\mathbf{2}}$ is $\mathbf{+}\mathbf{3}$.