$\mathrm{ZnO}\left(\mathrm{s}\right)+\mathrm{C}\left(\mathrm{s}\right)\to \mathrm{Zn}\left(\mathrm{g}\right)+\mathrm{CO}\left(\mathrm{g}\right)$ which substance is oxidized, reduced, and oxidizing agent?

• The given reaction $\underset{\mathrm{Zinc}\mathrm{oxide}}{\mathrm{ZnO}\left(\mathrm{s}\right)}+\underset{\mathrm{Carbon}}{\mathrm{C}\left(\mathrm{s}\right)}\to \underset{\mathrm{Zinc}}{\mathrm{Zn}\left(\mathrm{g}\right)}+\underset{\mathrm{Carbon}\mathrm{monoxide}}{\mathrm{CO}\left(\mathrm{g}\right)}$.
• The oxidation state of elements in reaction:
• $\underset{+2-2}{\mathrm{ZnO}}\left(\mathrm{s}\right)+\underset{0}{\mathrm{C}}\left(\mathrm{s}\right)\to \underset{0}{\mathrm{Zn}}\left(\mathrm{g}\right)+\underset{+2-2}{\mathrm{CO}}\left(\mathrm{g}\right)$
• 
• So, carbon is oxidized because there is an increase in its oxidation state, while zinc is reduced because there is a decrease in its oxidation state.
• The above reaction is an example of a redox reaction because carbon is oxidized and zinc is getting reduced simultaneously.

Changes in oxidation state

• $\mathrm{C}$ gets oxidized from the oxidation state $0to+2$.
• $\mathrm{Zn}$ gets reduced from the oxidation state $+2to0$.
• An oxidizing agent is $\mathrm{ZnO}$.