Question

Which gas is more soluble in water ${{\text{O}}_{\text{2}}}$ or ${{\text{N}}_{\text{2}}}$

Answer 1

To answer this question, you should recall the concept of solubility of a gas in a liquid. Use the concept of Henry’s law to answer this question.

Complete step by step answer:
Henry’s law is a gas law which states that the amount of gas that is dissolved in a liquid is directly proportional to the partial pressure of that gas above the liquid when the temperature is kept constant. Let us first define solubility. For any substance, solubility is the maximum amount of solute that can be dissolved in a given solvent at a particular temperature. The gas solubility in liquids is greatly affected by temperature and pressure as well as the nature of the solute and the solvent.
Oxygen and nitrogen are the two most abundant gases in the Earth’s atmosphere and have generally similar physical properties, yet ${{\text{O}}_{\text{2}}}$ is twice as soluble in water as ${{\text{N}}_{\text{2}}}$ due to higher values of Henry’s constant.

Note:
You should know about the Factors Affecting Solubility. It has been found that the gas solubility in liquids increases with increase in pressure. The gas molecules in a liquid are dissolved by the process of dissolution which is an exothermic reaction i.e. during this process heat is evolved. According to Le Chatelier’s Principle which states that when the equilibrium of a system is disturbed, the system readjusts itself in such a way that the effect that has caused the change in equilibrium is countered. Hence the solubility should decrease with an increase in temperature to validate Le Chatelier’s Principle.