Final answer:
An increase in pressure has little to no effect on the solubility of a solid like KNO3 in a liquid solvent such as water.
Step-by-step explanation:
The solubility of a substance such as potassium nitrate (KNO3) in water depends on various factors, including temperature and pressure. Based on solubility curves, we know that the solubility of KNO3 increases significantly with an increase in temperature. When discussing the effect of pressure on the solubility of a solid solute in a liquid solvent, it's generally understood that an increase in pressure has little to no effect on the solubility. The solubility of gases in liquids, however, does increase with an increase in pressure (Henry's Law). Therefore, an increase in pressure on the solution of KNO3 in water at 65 degrees Celsius will not have a notable effect on the solubility of KNO3.