Question

Which gas law explains why there is as much CO2 exchanged between the alveoli and blood as there is O2 exchanged, despite the fact that the partial pressure difference is so much smaller for CO2?

a.Henry's law
b.Boyle's law
c.Dalton's law

Answer 1

Henry's Law explains the equivalent gas exchange of CO2 and O2 between the alveoli and blood, because while CO2 has a smaller partial pressure difference, its solubility is much higher, enabling equal amounts of CO2 and O2 to be exchanged.

Step-by-step explanation:

The gas law that explains why there is as much CO2 exchanged between the alveoli and blood as there is O2 exchanged, despite the smaller partial pressure difference for CO2, is Henry's Law. Henry's Law states that the amount of a specific gas that dissolves in a liquid is a function of its partial pressure. The solubility of CO2 is much greater than that of oxygen, by a factor of about 20. Consequently, even though the partial pressure difference for CO2 (around 5 mm Hg) is smaller than that for O2, the amount of CO2 that dissolves in the blood is equivalent to the amount of O2 due to its higher solubility.

This effect is why, across the respiratory membrane in the alveoli, the relative concentrations of oxygen and carbon dioxide that diffuse are similar, allowing for efficient gas exchange even with differing partial pressures. The higher solubility of CO2 in both blood and alveolar fluids compensates for its lower partial pressure gradient compared to oxygen.