The correct option is **B. The temperature of the solvent**. ### Detailed Explanation: 1. **Understanding Solubility**: - Solubility is the ability of a solute (in this case, a solid) to dissolve in a solvent (a liquid). The extent to which a solute can dissolve in a solvent is influenced by several factors, but temperature is one of the most significant for solid solutes. 2. **Effect of Temperature**: - Generally, for most solid solutes, increasing the temperature of the solvent increases the solubility of the solute. This is because higher temperatures provide more kinetic energy to the molecules, allowing them to move more freely and interact more effectively with the solute particles. As a result, more solute can dissolve in the solvent. - For example, sugar dissolves more readily in hot water than in cold water. This is due to the increased energy that helps break the intermolecular forces holding the sugar molecules together. 3. **Why Other Options Are Incorrect**: - **A. The color of the solute**: The color of a solute does not affect its solubility. Color is a physical property related to the absorption and reflection of light, not to the interactions between solute and solvent molecules. - **C. The pressure of the solvent**: Pressure primarily affects the solubility of gases in liquids, not solids. For solids, changes in pressure have a negligible effect on solubility because solids are incompressible. Therefore, while pressure can influence gas solubility (as seen in carbonated beverages), it does not play a significant role in the solubility of solid solutes. - **D. The molecular weight of the solute**: While molecular weight can influence solubility to some extent (larger molecules may have different solubility characteristics), it is not a primary factor. Solubility is more closely related to the nature of the solute and solvent (like polarity) and temperature rather than just the molecular weight. ### Summary of Key Points: - **Temperature** is the primary factor affecting the solubility of solid solutes in liquid solvents. - Increasing temperature generally increases solubility for most solids. - The **color** of the solute does not influence solubility. - **Pressure** has minimal effect on solid solubility but is significant for gases. - **Molecular weight** can influence solubility but is not the main factor. ### Revision Summary: - Solubility of solid solutes is primarily affected by temperature. - Higher temperatures typically increase solubility. - Color and pressure do not significantly affect solid solubility. - Molecular weight has some influence but is secondary to temperature effects.