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 away from the solid structure 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 dissolve better at lower 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 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 the volume change associated with dissolving a solid is minimal compared to that of a gas. - **D. The pH of the solute**: While pH can affect the solubility of some compounds (especially those that are acidic or basic), it is not a primary factor for most solid solutes. The pH can influence the ionization of certain solutes, but it does not have a direct effect on the solubility of all solids in a liquid solvent. ### 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 collisions. - The color of the solute, pressure of the solvent, and pH of the solute do not significantly influence the solubility of solid solutes in a liquid solvent. ### Revision Summary - Solubility of solid solutes is primarily affected by temperature. - Higher temperatures increase kinetic energy, facilitating the dissolution process. - Color, pressure, and pH are not primary factors influencing solid solubility in liquids.