Question

Define Oxidation and Reduction reactions with suitable examples (Redox reactions).

Hint:

{Oxidation = Loss of electrons}
{Reduction = Gain of electrons}
Both processes occur together in a {redox reaction}.

Answer 1

Concept: In many chemical reactions, one substance loses electrons while another gains electrons. Such reactions are called oxidation-reduction reactions or redox reactions. Oxidation and reduction always occur simultaneously.
Step 1:Oxidation Reaction Oxidation is defined as the process in which a substance:

• loses electrons, or
• gains oxygen, or
• loses hydrogen.

Example: \[ 2Mg + O_2 \rightarrow 2MgO \] In this reaction, magnesium combines with oxygen to form magnesium oxide. Here, magnesium is oxidized because it gains oxygen.
Step 2:Reduction Reaction Reduction is defined as the process in which a substance:

• gains electrons, or
• loses oxygen, or
• gains hydrogen.

Example: \[ CuO + H_2 \rightarrow Cu + H_2O \] In this reaction, copper oxide loses oxygen and forms copper. Hence, copper oxide is reduced.
Step 3:Redox Reaction A redox reaction is a chemical reaction in which oxidation and reduction occur simultaneously. Example: \[ Zn + CuSO_4 \rightarrow ZnSO_4 + Cu \] Here:

• Zinc loses electrons and is oxidized.
• Copper ions gain electrons and are reduced.