Partial pressure of oxygen in alveolar air is

Question

Partial pressure of oxygen in alveolar air is

1. A. 159 mm Hg
2. B. 90 mm Hg
3. C. 104 mm Hg (Correct answer)
4. D. 45 mm Hg

Correct Answer

Option C — 104 mm Hg

Detailed Solution & Explanation

The correct answer is 104 mm Hg.

Key Points

• The partial pressure of O2 in alveolar air is approximately 104 mm Hg.
• Atmospheric O2 is 159 mm Hg, but it decreases in alveoli due to mixing with water vapor and CO2.