If solute volume is 4 mL and total volume is 20 mL, the dilution factor D equals

• A. 0.2
• B. 0.8
• C. 5
• D. 20

Answer: (A)

Dilution factor here is the fraction of the final mixture that comes from the original solute. It’s calculated as D = V_solute / V_total. With 4 mL of solute in a final 20 mL volume, D = 4 / 20 = 0.2. This means the diluted solution contains 0.2 times the original concentration (one-fifth of it). Some sources use the reciprocal (final volume over solute volume), which would be 5, but in this context the dilution factor is defined as the ratio of solute volume to total volume, so 0.2 is the correct value.