What is the total amount of drug present in the final 50 mL solution?

What is the total amount of drug present in the final 50 mL solution?

• A. 25 mg
• B. 50 mg
• C. 12.5 mg
• D. 100 mg

Answer: (A)

The amount of drug in the final solution is found by multiplying the final concentration by the final volume, because when you dilute a solution the same total amount of drug is spread out over a larger volume. If the final 50 mL solution has a concentration of 0.5 mg/mL, the total drug present is 0.5 mg/mL × 50 mL = 25 mg. So 25 mg is the total amount in that 50 mL solution. If the concentration were different, the total would change accordingly (for example, a concentration of 1 mg/mL would give 50 mg, etc.), but given the final concentration in this scenario, 25 mg is the correct total.

The amount of drug in the final solution is found by multiplying the final concentration by the final volume, because when you dilute a solution the same total amount of drug is spread out over a larger volume. If the final 50 mL solution has a concentration of 0.5 mg/mL, the total drug present is 0.5 mg/mL × 50 mL = 25 mg. So 25 mg is the total amount in that 50 mL solution. If the concentration were different, the total would change accordingly (for example, a concentration of 1 mg/mL would give 50 mg, etc.), but given the final concentration in this scenario, 25 mg is the correct total.