How many times more soluble is carbon dioxide (CO2) compared to oxygen (O2)?

Carbon dioxide (CO2) is significantly more soluble in water compared to oxygen (O2), primarily due to its chemical properties. CO2 can undergo hydration to form carbonic acid when it dissolves in water, while O2, being a nonpolar molecule, does not interact favorably with water and thus has a much lower solubility.

In physiological conditions, it is accepted that CO2 is approximately 20 times more soluble than O2. This higher solubility is particularly important in the context of gas exchange in the lungs, where CO2 removal from the body during respiration is facilitated by its ability to dissolve more readily in the blood plasma compared to O2. This property plays a substantial role in how organisms manage respiratory gas exchange, ensuring efficient elimination of CO2 and uptake of O2.