Which of the following factors would not affect the solubility of a gas?

Analyze the question: We need the factor that does NOT affect how much of a gas dissolves in a solvent.

Concept: Solubility of a gas depends on:

1. Pressure – By Henry's Law, the solubility of a gas is directly proportional to its partial pressure above the liquid (S = kP). This is why a fizzy drink bubbles when you open the bottle and the pressure drops.
2. Temperature – Gas solubility generally decreases as temperature rises. Warm water holds less dissolved oxygen than cold water.
3. Nature of solvent (and solute) – "Like dissolves like." For example, ammonia and HCl are very soluble in water because they react with or are attracted to it, while oxygen and nitrogen are only slightly soluble.

Going through the options:

• A. Concentration: Concentration describes how much solute is already in a solution. It is a result of solubility, not a factor that determines the solubility of the gas. So it is not an independent factor affecting solubility.
• B. Nature of solvent: Affects solubility, so it is not the answer.
• C. Pressure: Affects solubility (Henry's Law), so it is not the answer.
• D. Temperature: Affects solubility, so it is not the answer.

Answer: The factor that would not affect the solubility of a gas is Concentration, option A.

Tip: Remember the three real factors for gases with PTN: Pressure, Temperature, Nature of solvent. Anything outside these, like "concentration," is not a factor that controls solubility.