Why are dilutions performed?

• A. To increase the concentration.
• B. To change the pH.
• C. To purify the solvent.
• D. To reach the desired concentration.

Answer: (D)

Dilution is the process of lowering the concentration of a solution by adding solvent. In practice, you dilute to reach a specific, lower concentration that is appropriate for an assay or reaction. This isn't done to increase concentration or to purify the solvent, and while adding solvent can slightly affect pH, changing pH is not the primary goal of a dilution. By aiming for the target concentration, you ensure measurements are accurate and the reagents behave as expected within the method’s working range. So dilutions are performed to reach the desired concentration.