Question

Define Oxidation and Reduction with suitable examples.

Hint:

Oxidation involves loss of electrons or addition of oxygen, while reduction involves gain of electrons or removal of oxygen. Both processes occur simultaneously in redox reactions.

Answer 1

Concept: Oxidation and reduction are important chemical processes that occur together in many chemical reactions. These processes involve the transfer of electrons, addition or removal of oxygen, or removal or addition of hydrogen. Such reactions are collectively known as redox reactions.
Step 1:Oxidation.
Oxidation is defined as the loss of electrons, or the addition of oxygen, or the removal of hydrogen from a substance during a chemical reaction. Examples:

• When magnesium reacts with oxygen to form magnesium oxide: \[ 2Mg + O_2 \rightarrow 2MgO \] In this reaction, magnesium combines with oxygen, so magnesium is oxidized.
• Rusting of iron is another example of oxidation: \[ 4Fe + 3O_2 + xH_2O \rightarrow 2Fe_2O_3 \cdot xH_2O \] Here iron combines with oxygen and gets oxidized to form rust.

Step 2:Reduction.
Reduction is defined as the gain of electrons, or the removal of oxygen, or the addition of hydrogen to a substance during a chemical reaction. Examples:

• When copper oxide is heated with hydrogen: \[ CuO + H_2 \rightarrow Cu + H_2O \] In this reaction, copper oxide loses oxygen and forms copper, so copper oxide is reduced.
• Reduction also occurs during the extraction of metals from their ores.

Step 3:Relationship between Oxidation and Reduction.
Oxidation and reduction always occur together in a chemical reaction.

• When one substance undergoes oxidation, another substance undergoes reduction.
• Therefore, such reactions are called redox reactions.