Introduction: Percentage solution calculations MCQs With Answer help B. Pharm students master core pharmacy math used in compounding, dispensing, and quality control. This topic covers % w/v (grams per 100 mL), % w/w (grams per 100 g), % v/v (mL per 100 mL), dilution using C1V1 = C2V2, alligation, conversions to mg/mL, ratio strength (e.g., 1:1000), and ppm. You will practice preparing solutions from solids and liquids, adjusting strengths, accounting for density in w/w ↔ w/v conversions, and checking label claims. These skills ensure accurate dosing, safe extemporaneous preparations, and regulatory-compliant labeling in community and hospital pharmacy practice. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. Which statement best defines % w/v in pharmacy calculations?
- Grams of solute per 100 mL of solution
- Grams of solute per 100 g of solution
- Milliliters of solute per 100 mL of solvent
- Grams of solute per liter of solvent
Correct Answer: Grams of solute per 100 mL of solution
Q2. How many grams of NaCl are needed to prepare 250 mL of a 4% w/v solution?
- 4 g
- 8 g
- 10 g
- 12.5 g
Correct Answer: 10 g
Q3. What volume of a 70% v/v isopropyl alcohol stock is required to prepare 500 mL of 10% v/v solution?
- 50.0 mL
- 71.4 mL
- 100.0 mL
- 142.9 mL
Correct Answer: 71.4 mL
Q4. A 2% w/w ointment is to be prepared with a total weight of 60 g. How much drug is required?
- 0.12 g
- 1.2 g
- 2.0 g
- 12.0 g
Correct Answer: 1.2 g
Q5. Convert 5 mg/mL to percentage strength (% w/v).
- 0.05% w/v
- 0.5% w/v
- 5% w/v
- 50% w/v
Correct Answer: 0.5% w/v
Q6. How much water should be added to 200 mL of a 20% w/v solution to obtain a 5% w/v solution?
- 200 mL
- 400 mL
- 600 mL
- 800 mL
Correct Answer: 600 mL
Q7. A solution is 15% w/w with density 1.10 g/mL. What is its approximate % w/v?
- 13.6% w/v
- 15.0% w/v
- 16.5% w/v
- 18.0% w/v
Correct Answer: 16.5% w/v
Q8. A ratio strength of 1:500 (w/v) is equivalent to what percentage strength?
- 0.02% w/v
- 0.2% w/v
- 2% w/v
- 5% w/v
Correct Answer: 0.2% w/v
Q9. What is the ppm equivalent of 0.01% w/v (assuming aqueous solution)?
- 10 ppm
- 50 ppm
- 100 ppm
- 1000 ppm
Correct Answer: 100 ppm
Q10. Using alligation, what is the mixing ratio (95% v/v ethanol : water) to make 70% v/v ethanol?
- 14:5
- 5:14
- 25:70
- 70:25
Correct Answer: 14:5
Q11. How many grams of solute are present in 750 mL of an 8% w/v solution?
- 6 g
- 30 g
- 60 g
- 80 g
Correct Answer: 60 g
Q12. What volume of a 30% w/v stock solution is needed to prepare 1 L of a 3% w/v solution?
- 30 mL
- 90 mL
- 100 mL
- 300 mL
Correct Answer: 100 mL
Q13. For ointments and creams, which expression of strength is most appropriate?
- % w/v
- % v/v
- % w/w
- Ratio strength (w/v)
Correct Answer: % w/w
Q14. How many grams of base must be added to 100 g of a 12% w/w cream to make it 8% w/w (no drug loss)?
- 12.5 g
- 25 g
- 37.5 g
- 50 g
Correct Answer: 50 g
Q15. What volume of a 5% w/v NaCl solution is required to prepare 250 mL of 0.9% w/v NaCl?
- 22.5 mL
- 45 mL
- 90 mL
- 135 mL
Correct Answer: 45 mL
Q16. Mixing 300 mL of 20% w/v with 700 mL of 5% w/v yields what final % w/v?
- 7.5% w/v
- 9.5% w/v
- 10.0% w/v
- 12.5% w/v
Correct Answer: 9.5% w/v
Q17. If 30 mL of glycerin is diluted to 150 mL, what is the % v/v?
- 10% v/v
- 15% v/v
- 20% v/v
- 25% v/v
Correct Answer: 20% v/v
Q18. What is the concentration in mg/mL of a 2% w/v solution?
- 2 mg/mL
- 10 mg/mL
- 20 mg/mL
- 200 mg/mL
Correct Answer: 20 mg/mL
Q19. A solution is 2% w/v with density 1.05 g/mL. What is the approximate % w/w?
- 1.90% w/w
- 2.00% w/w
- 2.10% w/w
- 2.50% w/w
Correct Answer: 1.90% w/w
Q20. What volume of 95% v/v alcohol is needed to prepare 1 L of 70% v/v alcohol (assume volumes are additive)?
- 526.3 mL
- 666.7 mL
- 736.8 mL
- 850.0 mL
Correct Answer: 736.8 mL
Q21. A 10% w/v solution corresponds to 1 g of solute per 10 mL of solution.
- True
- False
- Only true for % v/v
- Only true for % w/w
Correct Answer: True
Q22. How many milliliters of a 2% w/v stock are needed to prepare 50 mL of a 0.1% w/v solution?
- 1.0 mL
- 2.5 mL
- 5.0 mL
- 10.0 mL
Correct Answer: 2.5 mL
Q23. A syrup labeled 65% w/w sucrose has density 1.32 g/mL. How many grams of sucrose are in 200 mL of syrup?
- 130.0 g
- 150.0 g
- 171.6 g
- 200.0 g
Correct Answer: 171.6 g
Q24. Which statement correctly describes % v/v?
- Milliliters of solute per 100 mL of solution (final volume)
- Milliliters of solute per 100 mL of solvent
- Grams of solute per 100 mL of solution
- Used only for gases, not liquids
Correct Answer: Milliliters of solute per 100 mL of solution (final volume)
Q25. Equal volumes of 5% w/v and 25% w/v solutions are mixed. What is the final % w/v?
- 10% w/v
- 12.5% w/v
- 15% w/v
- 20% w/v
Correct Answer: 15% w/v
Q26. What is the % w/w of an ointment prepared by triturating 0.5 g of drug with base to a total of 25 g?
- 0.5% w/w
- 1% w/w
- 2% w/w
- 5% w/w
Correct Answer: 2% w/w
Q27. How many grams of solute are needed to prepare 800 mL of a 0.05% w/v solution?
- 0.04 g
- 0.4 g
- 4 g
- 40 g
Correct Answer: 0.4 g
Q28. A reconstituted suspension labeled 125 mg/5 mL corresponds to what percentage strength (% w/v)?
- 0.25% w/v
- 1.25% w/v
- 2.5% w/v
- 5.0% w/v
Correct Answer: 2.5% w/v
Q29. A solution labeled 1:1000 (w/v) epinephrine is equivalent to which of the following?
- 0.1% w/v (1 mg/mL)
- 0.01% w/v (0.1 mg/mL)
- 1% w/v (10 mg/mL)
- 0.5% w/v (5 mg/mL)
Correct Answer: 0.1% w/v (1 mg/mL)
Q30. How many milliliters of a 10% w/v solution contain 3 g of solute?
- 3 mL
- 10 mL
- 30 mL
- 300 mL
Correct Answer: 30 mL
