### Correct Option: A. Filtration #### Detailed Explanation: To understand why filtration is the most appropriate method for separating a mixture of sand and salt, we need to consider the physical properties of both substances and how they interact with water. 1. **Nature of the Mixture**: - Sand is a solid that does not dissolve in water, while salt (sodium chloride) is soluble in water. This difference in solubility is key to the separation process. 2. **Filtration Process**: - **Step 1**: Add water to the mixture of sand and salt. The salt will dissolve in the water, creating a saltwater solution, while the sand will remain as solid particles. - **Step 2**: Use a filter paper placed in a funnel. The filter paper has tiny pores that allow liquid (the saltwater solution) to pass through while trapping the solid particles (sand). - **Step 3**: Collect the liquid that passes through the filter. This liquid contains the dissolved salt. - **Step 4**: The sand will remain on the filter paper, effectively separating it from the saltwater solution. 3. **Final Steps**: - To recover the salt from the saltwater solution, you can evaporate the water. This can be done by heating the solution until all the water evaporates, leaving behind the salt crystals. #### Why Other Options Are Incorrect: - **B. Distillation**: - Distillation is a method used to separate components of a mixture based on differences in boiling points. While it is effective for separating liquids or liquid mixtures, it is not suitable for separating a solid (sand) from a soluble solid (salt) in a mixture. In this case, distillation would not effectively separate sand from salt because sand does not vaporize. - **C. Chromatography**: - Chromatography is a technique used to separate components of a mixture based on their movement through a stationary phase under the influence of a mobile phase. It is typically used for separating colored substances or small amounts of compounds in a solution. Since sand and salt are not colored and do not require such a complex separation, chromatography is not appropriate for this mixture. - **D. Sublimation**: - Sublimation is the process where a solid changes directly into a gas without passing through a liquid phase. This method is useful for separating substances that can sublime (like iodine or dry ice) from those that do not. Since neither sand nor salt sublimates, this method is not applicable for separating them. ### Summary of Key Points: - **Filtration** is the best method for separating sand (insoluble) from salt (soluble) in water. - Sand remains as a solid while salt dissolves, allowing for effective separation. - Other methods like distillation, chromatography, and sublimation are not suitable for this specific mixture. - To recover salt after filtration, evaporate the water from the saltwater solution. This understanding of the properties of the substances involved and the appropriate separation techniques is crucial for effectively solving similar problems in chemistry.