The correct option is Both A and R are true and R is the correct explanation of A.
Explanation
Chemical reactions are classified based on energy exchange with the surroundings. Reactions that result in the release of energy (in the form of heat, light, or ATP) are termed exothermic reactions.
Analysis of Assertion (A): Correct. Respiration is scientifically classified as an exothermic reaction. This is because the process involves the breaking of chemical bonds in food molecules to release energy essential for life processes.
Analysis of Reason (R): Correct. The reason accurately describes the biochemical process of respiration. Carbohydrates are broken down into glucose during digestion. This glucose undergoes oxidation in the cells, combining with oxygen to yield carbon dioxide, water, and energy. The chemical equation is:
C6H12O6(aq) + 6O2(g) → 6CO2(aq) + 6H2O(l) + Energy
Justification: The Assertion states that respiration is exothermic. The Reason explains the mechanism: the combination of glucose and oxygen produces energy. Since the production of energy is the defining characteristic of an exothermic reaction, R is the correct explanation for A.
Key Takeaway: Respiration is an exothermic process because the oxidation of glucose releases energy.