Question

What do you understand by the term redox reaction?

Answer 1

Redox reaction: The reaction in which oxidation and reduction takes place simultaneously is known as a redox reaction.

• Oxidation - The addition of oxygen to a substance or removal of hydrogen from a substance is called oxidation.
• Reduction - The addition of hydrogen to a substance or removal of oxygen from a substance is called reduction.

Examples of redox reactions are :

1). $\mathrm{CuO}\left(\mathrm{s}\right)+{\mathrm{H}}_2\left(\mathrm{g}\right)\stackrel{}{\to }\mathrm{Cu}\left(\mathrm{s}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)$

Substance oxidised is ${\mathrm{H}}_2$ and substance reduced is $\mathrm{CuO}$.

2). $\mathrm{ZnO}\left(\mathrm{s}\right)+\mathrm{C}\left(\mathrm{s}\right)\stackrel{}{\to }\mathrm{Zn}\left(\mathrm{s}\right)+\mathrm{CO}\left(\mathrm{g}\right)$

Substance oxidised is $\mathrm{C}$ and substance reduced is $\mathrm{ZnO}$.

3). $2\mathrm{PbO}\left(\mathrm{s}\right)+\mathrm{C}\left(\mathrm{s}\right)\stackrel{}{\to }2\mathrm{Pb}\left(\mathrm{s}\right)+{\mathrm{CO}}_2\left(\mathrm{g}\right)$

Substance oxidised is $\mathrm{C}$ and substance reduced is $\mathrm{PbO}$.