Question

What is the partial pressure of carbon dioxide in alveolar air and in deoxygenated blood respectively?

(a) 50 mm Hg, 45 mm Hg

(b) 104 mm Hg, 45 mm Hg

(c) 45 mm Hg, 40 mm Hg

(d) 40 mm Hg, 45 mm Hg

I have been asked this question in class test.

The doubt is from Exchange of Gases in chapter Breathing and Exchange of Gases of Biology – Class 11

Answer 1

Correct option is (d) 40 mm Hg, 45 mm Hg

To elaborate: In alveolar air, partial pressure of carbon dioxide is 40 mm Hg and its value in deoxygenated blood is 45 mm Hg. So, carbon dioxide moves from arterial blood to alveoli. In this way, according to partial pressure exchange of gases takes place.