Question

Which of the following is true for $CO_2$ concentration?

• A. More in alveolar air than in expired air
• B. More in expired air than in alveolar air
• C. More in inspired air than in alveolar air
• D. More in inspired air than in expired air

Answer 1

Answer: (A)

More in alveolar air than in expired air

Answer 2

Concentration or partial pressure of $CO_2\, (PCO_2)$ is $40 \,mm \,Hg$ in alveolar air and $32 \,mm \,Hg$ in expired air.