Final answer:
The solubility of sulfur dioxide gas in water is most affected by a change in pressure, as described by Henry's law, which states that the solubility of a gas is directly proportional to its pressure above the liquid. Solids and liquids' solubility are not significantly affected by pressure.
Step-by-step explanation:
The solubility of a solute in water that would be most affected by a change in pressure at room temperature is sulfur dioxide (gas). According to Henry's law, the solubility of a gas in a liquid is directly proportional to the partial pressure of that gas above the liquid. This means that gases like sulfur dioxide will have their solubility significantly altered with changes in pressure. In contrast, solids like potassium nitrate or sugar, and liquids like ethanol are not substantially affected by pressure changes when it comes to solubility in water.
When considering Henry's law, it is expressed as Cg=kPg, where Cg is the solubility of the gas, Pg is the partial pressure of the undissolved gas above the solution, and k is Henry's law constant. For gases, increasing the pressure increases their solubility, while decreasing the pressure decreases their solubility. These principles are utilized in carbonated beverages, where carbon dioxide is dissolved in the liquid under high pressure to create the carbonation.