The correct option is **B. Sand**. ### Explanation of the Correct Answer **Filtration Process:** Filtration is a physical separation 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 are looking to separate sodium chloride (NaCl) from an aqueous mixture. **Components of the Mixture:** 1. **Sodium Chloride (NaCl)**: This is a soluble salt that dissolves in water to form a homogeneous solution. 2. **Sand**: Sand is an insoluble solid that does not dissolve in water. **Separation Mechanism:** When you perform filtration on a mixture of sodium chloride and sand: - The sand particles will be retained on the filter paper because they are too large to pass through the pores of the filter. - The sodium chloride, being dissolved in the water, will pass through the filter along with the water, resulting in a clear filtrate (the liquid that passes through). After filtration, you can then evaporate the water from the filtrate to obtain pure sodium chloride crystals. ### Why the Other Options are Incorrect **A. Potassium Nitrate (KNO3)**: - Potassium nitrate is also a soluble salt, similar to sodium chloride. If you were to filter a mixture of sodium chloride and potassium nitrate, both would pass through the filter paper because they are dissolved in the water. Therefore, filtration would not separate them, making this option incorrect. **C. Lead Nitrate (Pb(NO3)2)**: - Lead nitrate is another soluble salt. Like potassium nitrate, it dissolves in water. If you filter a mixture of sodium chloride and lead nitrate, both would remain in the solution and pass through the filter. Thus, this option is also incorrect. **D. Sugar (Glucose)**: - Sugar is a soluble organic compound that dissolves in water. If you have a mixture of sodium chloride and sugar, both will pass through the filter during the filtration process. Therefore, this option does not provide a means to separate sodium chloride from the mixture. ### Summary of Key Points - **Filtration** is effective for separating insoluble solids from liquids. - **Sodium chloride** is soluble in water, while **sand** is not, allowing for effective separation. - Other options (potassium nitrate, lead nitrate, and sugar) are all soluble in water and cannot be separated from sodium chloride using filtration. - After filtration, evaporation of the filtrate can yield pure sodium chloride. ### Revision Summary - Filtration separates insoluble solids from liquids. - Sodium chloride is soluble; sand is not, making them separable by filtration. - Other options (potassium nitrate, lead nitrate, sugar) are soluble and cannot be separated from sodium chloride by this method. - Evaporation of the filtrate can recover pure sodium chloride after filtration.