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**: - **Kinetic Energy**: As the temperature of the solvent increases, the kinetic energy of the solvent molecules also increases. This means that the molecules move faster and collide more frequently and with greater energy. - **Dissolution Process**: For a solid solute to dissolve, the solute particles must break apart and interact with the solvent molecules. Higher temperatures facilitate this process by providing the energy needed to overcome the intermolecular forces holding the solute particles together. - **Endothermic vs. Exothermic Dissolution**: Most solid solutes dissolve endothermically, meaning they absorb heat. Therefore, increasing the temperature generally increases solubility. However, there are exceptions (e.g., some salts may have decreased solubility at higher temperatures), but for the majority of solid solutes, higher temperatures lead to increased solubility. 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 property related to the electronic structure of the molecules and how they interact with light, not how they interact with a solvent. - **C. The size of the solute particles**: While the size of solute particles can influence the rate of dissolution (smaller particles dissolve faster due to a larger surface area), it does not primarily affect the overall solubility. Solubility is more about the interactions between solute and solvent rather than just the size of the solute. - **D. The pressure applied to the solution**: Pressure has a significant effect on the solubility of gases in liquids (as described by Henry's Law), but it has a negligible effect on the solubility of solids in liquids. For solids, pressure changes do not significantly alter the solubility because solids are incompressible. ### Summary of Key Points - **Temperature** is the primary factor affecting the solubility of solid solutes in liquid solvents. - Increased temperature generally increases the solubility of solid solutes due to higher kinetic energy and more effective interactions with solvent molecules. - The **color** of the solute, **size of the solute particles**, and **pressure** applied to the solution do not primarily influence solubility in the same way that temperature does. ### Revision Summary - Solubility of solid solutes is primarily affected by temperature. - Higher temperatures increase kinetic energy, enhancing solute dissolution. - Color and size of solute particles do not significantly affect solubility. - Pressure has minimal impact on solid solute solubility in liquids.