The correct option for separating a mixture of sand and salt in water is **B. Filtration**. ### Detailed Explanation 1. **Understanding the Mixture**: - The mixture consists of sand, salt, and water. Sand is a solid that does not dissolve in water, while salt (sodium chloride) is soluble in water. This means that when you mix them, the sand will remain as solid particles, while the salt will dissolve and form a solution with the water. 2. **Separation Technique**: - **Filtration** is a method used to separate solids from liquids or gases using a filter medium that allows only the fluid to pass through while retaining the solid particles. In this case, we can use filtration to separate the sand from the saltwater solution. 3. **Process of Filtration**: - **Step 1**: Set up a filtration apparatus, which typically consists of a funnel and filter paper placed inside the funnel. - **Step 2**: Pour the mixture of sand, salt, and water into the funnel. - **Step 3**: The sand particles will be trapped on the filter paper, while the saltwater solution will pass through the filter and collect in a container below. - **Step 4**: After filtration, you will have two components: the sand retained on the filter paper and the saltwater solution collected in the container. 4. **Recovering the Salt**: - If you want to recover the salt from the saltwater solution, you can use **evaporation**. By heating the saltwater, the water will evaporate, leaving behind the salt as a solid. ### Why Other Options Are Incorrect - **A. Distillation**: - Distillation is a technique used to separate components of a mixture based on differences in boiling points. It is not suitable for separating sand from saltwater because sand does not evaporate, and the boiling point of water is much lower than that of salt. Therefore, distillation would not effectively separate sand from the mixture. - **C. Chromatography**: - Chromatography is primarily used for separating and analyzing compounds that are in a mixture, especially in solutions. It is not suitable for separating solid particles like sand from a liquid mixture. Chromatography is more effective for separating colored substances or small amounts of dissolved substances. - **D. Centrifugation**: - Centrifugation involves spinning a mixture at high speeds to separate components based on their density. While it can separate solids from liquids, it is not as straightforward or efficient for separating sand from saltwater as filtration. Additionally, sand is relatively heavy and would settle quickly, making filtration a more practical choice. ### Summary of Key Points - **Filtration** is the most suitable method for separating sand from a saltwater mixture because it effectively retains solid particles while allowing liquids to pass through. - **Distillation** is not effective for this mixture due to the differing states of the components. - **Chromatography** is not applicable for solid-liquid separation in this case. - **Centrifugation** is less efficient than filtration for this specific separation task. By understanding the properties of the components in the mixture and the principles behind each separation technique, you can choose the most effective method for any given situation.