Question

The process of burning carbon or carbon compounds in excess of oxygen is called _____.

• A. Reduction
• B. Physical change
• C. Combustion
• D. Fermentation

Hint:

Combustion always involves:
• Oxygen
• Heat production
• Formation of new substances Complete combustion of carbon compounds generally produces: \[ CO_2 + H_2O \]

Answer 1

The Correct Option is C

Concept:
When a substance reacts chemically with oxygen and releases heat energy, the process is known as combustion. Combustion is generally associated with burning substances such as coal, wood, petrol, diesel, LPG, methane, and other carbon-containing compounds. Carbon and carbon compounds undergo combustion in the presence of oxygen to produce:
• Carbon dioxide
• Heat energy
• Sometimes light energy The general combustion reaction is: \[ \text{Carbon compound} + O_2 \rightarrow CO_2 + H_2O + \text{Heat} \] Combustion is an exothermic process because energy is released during the reaction.

Step 1: Understand the meaning of burning.
The question states: \[ \text{``burning carbon or carbon compounds in excess oxygen''} \] Burning means reacting with oxygen. When carbon burns completely in sufficient oxygen: \[ C + O_2 \rightarrow CO_2 + \text{Heat} \] Similarly, hydrocarbons also burn in oxygen producing carbon dioxide and water.

Step 2: Examine each option carefully.
Option (A): Reduction
Reduction means:
• Removal of oxygen, or
• Addition of hydrogen This is opposite to combustion in many cases. Hence, this option is incorrect. Option (B): Physical change
A physical change does not produce a new substance. Combustion forms new substances like: \[ CO_2 \text{ and } H_2O \] Therefore combustion is a chemical change, not a physical change. Hence, this option is incorrect. Option (C): Combustion
Combustion is exactly the process of burning substances in oxygen. Hence, this option is correct. Option (D): Fermentation
Fermentation is a biochemical process involving microorganisms such as yeast. Example: \[ \text{Sugar} \rightarrow \text{Alcohol} \] This process is unrelated to burning. Hence, this option is incorrect.

Step 3: Choose the correct answer.
Therefore, the process of burning carbon or carbon compounds in excess oxygen is called: \[ \boxed{\text{Combustion}} \] Hence, \[ \boxed{(3)\ \text{Combustion}} \]