**Correct Option: C. Pressure of the surrounding environment** ### Detailed Explanation: To understand why option C is the correct answer, we need to analyze how each of the listed factors affects the solubility of a solid solute in a liquid solvent. #### A. Temperature of the solvent - **Effect on Solubility**: The temperature of the solvent is one of the most significant factors affecting the solubility of solid solutes. Generally, as the temperature increases, the solubility of most solid solutes in liquids also increases. This is because higher temperatures provide more kinetic energy to the molecules, allowing them to break apart and interact with the solvent more effectively. - **Example**: For instance, sugar dissolves more readily in hot water than in cold water. #### B. Stirring or agitation of the solution - **Effect on Solubility**: Stirring or agitating a solution can enhance the rate at which a solid solute dissolves in a solvent. While it does not change the solubility limit (the maximum amount of solute that can dissolve at a given temperature), it helps distribute the solute particles throughout the solvent more quickly, allowing for faster dissolution. - **Example**: When you stir a cup of coffee while adding sugar, the sugar dissolves faster than if you let it sit still. #### C. Pressure of the surrounding environment - **Effect on Solubility**: Pressure has a negligible effect on the solubility of solid solutes in liquid solvents. This is because solids and liquids are relatively incompressible, meaning that changes in pressure do not significantly alter the interactions between solute and solvent molecules. Pressure is more relevant when discussing the solubility of gases in liquids, where increased pressure can lead to greater solubility. - **Example**: The solubility of salt in water is not significantly affected by changes in atmospheric pressure. #### D. Nature of the solute and solvent - **Effect on Solubility**: The chemical nature of both the solute and the solvent plays a crucial role in solubility. This includes factors such as polarity, molecular size, and intermolecular forces. For example, polar solutes tend to dissolve well in polar solvents (like salt in water), while nonpolar solutes dissolve better in nonpolar solvents (like oil in hexane). - **Example**: Oil does not dissolve in water due to the differences in polarity. ### Why the Other Options Are Incorrect or Weaker: - **Option A (Temperature)**: This is a significant factor; thus, it cannot be the correct answer. - **Option B (Stirring)**: While it affects the rate of dissolution, it does not change the solubility limit, but it is still a relevant factor in the process of dissolving. - **Option D (Nature of solute and solvent)**: This is fundamental to understanding solubility and is a critical factor in determining whether a solute will dissolve in a solvent. ### Summary: - **Temperature**: Higher temperatures generally increase solubility for solids. - **Stirring**: Enhances the rate of dissolution but does not affect solubility limits. - **Pressure**: Has little to no effect on the solubility of solids in liquids. - **Nature of solute/solvent**: Critical for determining solubility compatibility. In conclusion, the factor that does NOT significantly affect the solubility of a solid solute in a liquid solvent is **C. Pressure of the surrounding environment**.