Which statement best describes the process of making a solution by diluting a stock solution?

• A. A measured mass of solute is added directly to the stock solution to increase its concentration.
• B. The stock solution is evaporated to reduce its volume and increase its concentration.
• C. The stock solution is filtered to remove impurities before use.
• D. A measured volume of stock solution is mixed with solvent to achieve a lower concentration.

Answer: (D)

Verified step by step guidance

1. Understand that dilution involves decreasing the concentration of a solution by adding more solvent, not by adding more solute or removing solvent.
2. Recognize that a stock solution is a concentrated solution that can be diluted to a desired lower concentration by mixing a measured volume of it with solvent.
3. Recall the dilution equation: \(C_1 \times V_1 = C_2 \times V_2\), where \(C_1\) and \(V_1\) are the concentration and volume of the stock solution, and \(C_2\) and \(V_2\) are the concentration and volume after dilution.
4. Note that adding solute directly to the stock solution would increase concentration, which is opposite to dilution.
5. Understand that evaporating the stock solution reduces volume and increases concentration, which is also opposite to dilution; filtering removes impurities but does not change concentration.