Pharmaceutical Calculations MCQs – 30 Questions with Answers

Pharmaceutical Calculations MCQs – 30 Questions with Answers

Pharmaceutical calculations are the backbone of accurate dispensing and patient safety. Whether you’re preparing for the Nepal Pharmacy Council License Exam or Loksewa Exams, mastering these calculations is crucial. This set of 30 advanced Multiple-Choice Questions (MCQs) covers essential topics including dose calculation, solution preparation, parts per million (PPM), the alligation method, moles, and more. Each question includes the correct answer to help you practice effectively and build confidence.

Ideal for pharmacy students, professionals, and exam aspirants — let’s sharpen your calculation skills!

1. What is the weight in grams of NaCl needed to prepare 500 mL of a 0.9% w/v solution?

A. 4.5 g
B. 0.45 g
C. 9 g
D. 2.25 g
Answer: A
(0.9 g/100 mL × 500 mL = 4.5 g)

2. How many moles are present in 10 g of NaCl (Molar mass = 58.5 g/mol)?

A. 0.17 mol
B. 5.85 mol
C. 1.7 mol
D. 0.1 mol
Answer: A
(10 / 58.5 = 0.17 mol)

3. How many grams of glucose (C₆H₁₂O₆, M.W. = 180) are required to make 250 mL of 5% w/v solution?

A. 12.5 g
B. 25 g
C. 10 g
D. 5 g
Answer: A
(5 g/100 mL × 250 mL = 12.5 g)

4. How many mL of a 10% solution should be used to prepare 100 mL of a 2% solution using water?

A. 80 mL
B. 20 mL
C. 10 mL
D. 25 mL
Answer: B
(C₁V₁ = C₂V₂ → 10×V = 2×100 → V = 20 mL)

5. How many mL of alcohol 95% and water (0%) are needed to make 1000 mL of 60% alcohol?

A. 650 mL alcohol, 350 mL water
B. 400 mL alcohol, 600 mL water
C. 316 mL alcohol, 684 mL water
D. 500 mL each
Answer: C
(Alligation: 95–60 = 35; 60–0 = 60 → Ratio = 60:35 = 12:7 → 12/19 × 1000 = 631.6 mL water, 368.4 mL alcohol)

6. Convert 300 ppm to % strength.

A. 0.03%
B. 0.3%
C. 3%
D. 0.003%
Answer: A
(300 ppm = 300 mg/L = 0.03%)

7. Convert 0.04% to ppm.

A. 4000 ppm
B. 400 ppm
C. 40 ppm
D. 4 ppm
Answer: B
(0.04% = 0.04 g/100 mL = 400 mg/L = 400 ppm)

8. A prescription reads: Ampicillin 250 mg q.i.d × 5 days. How many grams are needed?

A. 5 g
B. 2.5 g
C. 10 g
D. 1.25 g
Answer: A
(250 mg × 4 × 5 = 5000 mg = 5 g)

9. The doctor orders 75 mg of a drug. You have 150 mg/2 mL ampoule. How many mL will you give?

A. 1 mL
B. 0.5 mL
C. 2 mL
D. 1.5 mL
Answer: A
(C₁V₁ = C₂V₂ → 150×X = 75×2 → X = 1 mL)

10. How many grams of NaCl are in 250 mL of 0.45% saline?

A. 1.125 g
B. 0.45 g
C. 0.9 g
D. 2.25 g
Answer: A
(0.45/100 × 250 = 1.125 g)

11. How many mL of a 20% solution and a 5% solution are needed to prepare 100 mL of a 10% solution?

A. 50 mL each
B. 33.3 mL of 20% and 66.7 mL of 5%
C. 75 mL of 20% and 25 mL of 5%
D. 25 mL of 20% and 75 mL of 5%
Answer: B
(33.3 mL of 20% and 66.7 mL of 5%)

12. How many liters of a 15% solution can be made from 1.5 kg of solute?

A. 5 L
B. 10 L
C. 15 L
D. 2.25 L
Answer: A
(15% = 15 g/100 mL → 1500 g/15 = 10,000 mL = 10 L)

13. A 0.02 M solution contains how many moles in 250 mL?

A. 0.005 mol
B. 0.02 mol
C. 0.25 mol
D. 0.05 mol
Answer: A
(0.02 mol/L × 0.25 L = 0.005 mol)

14. A patient is prescribed 0.25 mg/kg of a drug. The patient weighs 60 kg. How much drug is required?

A. 15 mg
B. 0.25 g
C. 25 mg
D. 30 mg
Answer: A
(0.25 × 60 = 15 mg)

15. How many mL of stock 1:1000 adrenaline are required to prepare 100 mL of 1:10,000 solution?

A. 1 mL
B. 5 mL
C. 10 mL
D. 2 mL
Answer: A
(Use dilution: C₁V₁ = C₂V₂ → 1/1000 × V = 1/10000 × 100 → V = 10 mL)

16. A prescription requires 60 mEq of NaCl. How many grams is this? (1 mEq of Na+ = 23 mg)

A. 1.38 g
B. 2.76 g
C. 3.45 g
D. 1.00 g
Answer: B
(60 × 23 = 1380 mg = 1.38 g)

17. What volume of 10% solution contains 1.5 g of drug?

A. 10 mL
B. 15 mL
C. 25 mL
D. 50 mL
Answer: B
(10% = 10 g/100 mL → 1.5 g = 15 mL)

18. Calculate the % strength w/v of 15 g of drug in 300 mL.

A. 2%
B. 5%
C. 7.5%
D. 10%
Answer: B
(15 g/300 mL × 100 = 5%)

19. 1 mole of H₂SO₄ contains how many grams? (M.W. = 98 g/mol)

A. 49 g
B. 98 g
C. 100 g
D. 196 g
Answer: B

20. The % concentration of a solution containing 0.25 g of a substance in 50 mL is:

A. 0.25%
B. 0.5%
C. 1%
D. 2%
Answer: B
(0.25 g / 50 mL × 100 = 0.5%)

21. Convert 500 ppm to %

A. 0.05%
B. 0.5%
C. 5%
D. 0.005%
Answer: A

22. A solution has 2 g of solute in 100 mL. What is the concentration in % w/v?

A. 1%
B. 2%
C. 3%
D. 4%
Answer: B

23. How many grams of NaOH (MW = 40) are needed to make 2M, 250 mL solution?

A. 10 g
B. 20 g
C. 15 g
D. 5 g
Answer: B
(2 mol/L × 0.25 L × 40 g/mol = 20 g)

24. Convert 1 in 500 solution to % strength.

A. 0.2%
B. 0.5%
C. 1%
D. 2%
Answer: A
(1 ÷ 500 × 100 = 0.2%)

25. 500 mg in 500 mL equals how many ppm?

A. 10 ppm
B. 100 ppm
C. 1000 ppm
D. 500 ppm
Answer: B
(500 mg / 0.5 L = 1000 mg/L = 1000 ppm)

26. What is the strength in % of 1 in 1000 solution?

A. 0.1%
B. 1%
C. 0.01%
D. 0.001%
Answer: A

27. The doctor orders 120 mg of drug. Available: 30 mg/mL. How many mL to give?

A. 2 mL
B. 4 mL
C. 6 mL
D. 8 mL
Answer: C

28. A 500 mL solution contains 1000 ppm of solute. How many mg of solute is present?

A. 1000 mg
B. 500 mg
C. 50 mg
D. 2000 mg
Answer: B
(1000 ppm = 1000 mg/L → 0.5 L = 500 mg)

29. You have 5% solution. How many mL needed to get 250 mg of drug?

A. 5 mL
B. 50 mL
C. 2.5 mL
D. 10 mL
Answer: D
(5% = 50 mg/mL → 250 ÷ 50 = 5 mL)

30. A solution contains 200 mg/100 mL. Express this as a ratio strength.

A. 1 in 5
B. 1 in 50
C. 1 in 500
D. 1 in 1000
Answer: C
(200 mg = 0.2 g → 0.2 g in 100 mL = 1 in 500)

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