Question

Which gas is liberated during respiration?

• A. O\textsubscript{2}
• B. SO\textsubscript{2}
• C. NO\textsubscript{2}
• D. CO\textsubscript{2}

Hint:

Exhaled air has higher CO\textsubscript{2} and lower O\textsubscript{2} than inhaled air.

Answer 1

The Correct Option is D

Step 1: Concept.
In aerobic respiration, glucose is oxidised using oxygen to form carbon dioxide and water with release of energy.
Step 2: Equation.
C\textsubscript{6}H\textsubscript{12}O\textsubscript{6} + 6O\textsubscript{2} $\rightarrow$ 6CO\textsubscript{2} + 6H\textsubscript{2}O + Energy.
Step 3: Conclusion.
Therefore, CO\textsubscript{2} is liberated.