Question

What do you understand by redox reactions? Explain oxidation and reduction in terms of loss or gain of electrons.

Answer 1

Redox reactions:

The reactions in which the reduction and oxidation processes occur simultaneously are called redox reactions.

Example: The reaction consists of reduction of Copper (Cu⁺²) ions to Copper (Cu) and oxidation of Zinc (Zn) to Zinc ions (Zn⁺²)

$$\begin{gathered} \mathrm{Zn}\left(\mathrm{s}\right)+{\mathrm{Cu}}^{+2}\left(\mathrm{aq}\right)\to {\mathrm{Zn}}^{+2}\left(\mathrm{aq}\right)+\mathrm{Cu}\left(\mathrm{s}\right) \\ \left(\mathrm{Zinc}\right)(\mathrm{Copper}\mathrm{ion})(\mathrm{Zinc}\mathrm{ion})\left(\mathrm{Copper}\right) \end{gathered}$$

Oxidation:

Oxidation is said to take place when there is a loss of electrons. In the reaction given below, there is a loss of two electrons.

$$\begin{gathered} \mathrm{Zn}\left(\mathrm{s}\right)\to {\mathrm{Zn}}^{+2}\left(\mathrm{aq}\right)+2{\mathrm{e}}^{-} \\ \left(\mathrm{Zinc}\right)(\mathrm{Zinc}\mathrm{ion}) \end{gathered}$$

Reduction:

Reduction is said to take place when there is a gain of electrons. In the reaction given below, there is a gain of two electrons.

$$\begin{gathered} {\mathrm{Cu}}^{+2}\left(\mathrm{aq}\right)+2{\mathrm{e}}^{-}\to \mathrm{Cu}\left(\mathrm{s}\right) \\ (\mathrm{Copper}\mathrm{ion})\left(\mathrm{Copper}\right) \end{gathered}$$