Question

Partial pressure of oxygen in alveolar air is ________

(a) 159 mm Hg

(b) 90 mm Hg

(c) 104 mm Hg

(d) 45 mm Hg

I have been asked this question at a job interview.

My query is from Exchange of Gases in chapter Breathing and Exchange of Gases of Biology – Class 11

Answer 1

The correct choice is (c) 104 mm Hg

Explanation: The Partial pressure of oxygen in alveolar air is 104 mm Hg, its value in arterial blood is 40 mm Hg. So, oxygen goes from alveolar air to arterial air. At the time of diffusion, gases move from high partial pressure to low partial pressure.