Question

Which gas has higher solubility in blood?

• A. Oxygen
• B. Nitrogen
• C. Carbon dioxide
• D. Hydrogen

Hint:

High solubility of \(CO_2\) is the reason why it can be transported in significant amounts in the dissolved state in plasma compared to oxygen.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Solubility is the physical property of a gas to dissolve in a liquid (blood or plasma) at a constant temperature and pressure. It determines the rate of diffusion across the respiratory membrane.

Step 2: Detailed Explanation:
The solubility of carbon dioxide (\(CO_2\)) is much higher than that of oxygen (\(O_2\)).
In physiological conditions, \(CO_2\) is approximately \(20\) to \(25\) times more soluble in blood and plasma than oxygen.
Because of this high solubility, \(CO_2\) can diffuse across the alveolar-capillary membrane much more efficiently than oxygen, even though the partial pressure gradient for \(CO_2\) (\(5\) mmHg) is much smaller than for \(O_2\) (\(64\) mmHg).
Nitrogen and Hydrogen have very low solubility in blood at normal physiological pressures.

Step 3: Final Answer:
Among the options, Carbon dioxide has the highest solubility in blood.