Weights and measures (Imperial & Metric system) MCQs With Answer

Introduction

Mastery of weights and measures is essential in B. Pharm for safe and accurate pharmacy calculations, compounding, and dispensing. This topic covers the Metric (SI) system and the Imperial/apothecaries’ system, including key units (kg, g, mg, mL, fl oz, grain, minim), unit conversions, specific gravity, percent strength (w/v, w/w, v/v), ratio strength, mEq, and osmolarity. Understanding household measures (teaspoon, tablespoon, cup), approximate vs exact equivalents (e.g., 1 oz = 28.35 g; 1 fl oz = 29.57 mL), and how to apply formulas (C1V1=C2V2) reduces dosing errors. Emphasis on significant figures, temperature references, and context (US vs UK units) ensures reliable conversions in clinical and industrial settings. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. Which is the SI base unit for mass used in pharmacy measurements?

• Gram (g)
• Kilogram (kg)
• Mole (mol)
• Newton (N)

Correct Answer: Kilogram (kg)

Q2. One grain (gr) equals approximately how many milligrams?

• 60 mg
• 64.8 mg
• 50 mg
• 62.5 mg

Correct Answer: 64.8 mg

Q3. One avoirdupois ounce (oz) equals approximately how many grams?

• 25 g
• 28.35 g
• 30 g
• 31.1 g

Correct Answer: 28.35 g

Q4. One avoirdupois pound (lb) is approximately equal to:

• 500 g
• 454 g
• 400 g
• 480 g

Correct Answer: 454 g

Q5. One US fluid ounce (fl oz) is approximately equal to:

• 28.41 mL
• 29.57 mL
• 30 mL
• 25 mL

Correct Answer: 29.57 mL

Q6. A standard household teaspoonful equals:

• 3 mL
• 4 mL
• 5 mL
• 10 mL

Correct Answer: 5 mL

Q7. A standard household tablespoonful equals:

• 10 mL
• 12.5 mL
• 15 mL
• 20 mL

Correct Answer: 15 mL

Q8. One US pint is approximately equal to:

• 500 mL
• 480 mL
• 473 mL
• 450 mL

Correct Answer: 473 mL

Q9. Convert 2.5 kg to pounds (lb):

• 4.0 lb
• 5.51 lb
• 6.2 lb
• 7.0 lb

Correct Answer: 5.51 lb

Q10. Specific gravity (SG) is best defined as the:

• Ratio of density of a substance to the density of water at the same temperature
• Mass per unit volume in g/mL
• Weight in air to weight in vacuum
• Percent strength of a solution

Correct Answer: Ratio of density of a substance to the density of water at the same temperature

Q11. A 10% w/v solution contains how many mg of solute per mL?

• 10 mg/mL
• 100 mg/mL
• 1 mg/mL
• 1000 mg/mL

Correct Answer: 100 mg/mL

Q12. A prescription orders 2 teaspoonfuls every 6 hours. What is the total daily volume administered?

• 20 mL
• 30 mL
• 40 mL
• 60 mL

Correct Answer: 40 mL

Q13. In water, 1 ppm corresponds to:

• 1 g/L
• 1 mg/mL
• 1 mg/L
• 1 μg/L

Correct Answer: 1 mg/L

Q14. Approximately how many grains are in 150 mg?

• 1 gr
• 2.3 gr
• 3 gr
• 5 gr

Correct Answer: 2.3 gr

Q15. One fluid dram (fl dr) is approximately equal to:

• 3.7 mL
• 5 mL
• 15 mL
• 30 mL

Correct Answer: 3.7 mL

Q16. The commonly used SI-derived unit for volume in pharmacy is:

• liter (L)
• gallon
• pint
• quart

Correct Answer: liter (L)

Q17. If a liquid has SG = 1.20 at 20°C, its density is approximately:

• 0.83 g/mL
• 1.00 g/mL
• 1.20 g/mL
• 1.50 g/mL

Correct Answer: 1.20 g/mL

Q18. Which step is essential when converting a concentration from mg/dL to mmol/L?

• Convert mg/dL to mg/L and then divide by the substance’s molecular weight
• Multiply by Avogadro’s number
• Add the solution’s density
• Multiply by the valence

Correct Answer: Convert mg/dL to mg/L and then divide by the substance’s molecular weight

Q19. 0.9% w/v sodium chloride contains how many mg per mL?

• 0.9 mg/mL
• 9 mg/mL
• 90 mg/mL
• 900 mg/mL

Correct Answer: 9 mg/mL

Q20. For monovalent ions (e.g., Na⁺), 1 mEq equals how many mmol?

• 0.5 mmol
• 1 mmol
• 2 mmol
• 10 mmol

Correct Answer: 1 mmol

Q21. Assuming complete dissociation, the osmolarity of 0.25 M NaCl is approximately:

• 0.25 Osm/L
• 0.5 Osm/L
• 1.0 Osm/L
• 2.0 Osm/L

Correct Answer: 0.5 Osm/L

Q22. One US cup (household measure) is approximately:

• 200 mL
• 236 mL
• 240 mL
• 250 mL

Correct Answer: 240 mL

Q23. How many grams of drug are present in 60 g of a 5% w/w ointment?

• 2 g
• 3 g
• 5 g
• 6 g

Correct Answer: 3 g

Q24. A ratio strength of 1:1000 (w/v) is equivalent to:

• 1%
• 0.1%
• 0.01%
• 10%

Correct Answer: 0.1%

Q25. How many mL of 95% v/v ethanol are needed to prepare 250 mL of 70% v/v ethanol? (Assume volume additivity.)

• 175 mL
• 184.2 mL
• 190 mL
• 200 mL

Correct Answer: 184.2 mL

Q26. Using alligation, what is the mixing ratio (parts) of 10% and 40% solutions to obtain 25%?

• 1:1
• 1:2
• 2:1
• 3:1

Correct Answer: 1:1

Q27. One minim (♏︎) equals approximately:

• 0.0616 mL
• 0.1 mL
• 0.616 mL
• 1.0 mL

Correct Answer: 0.0616 mL

Q28. At standard conditions, the mass of 1 liter of water is approximately:

• 100 g
• 500 g
• 1 kg
• 2 kg

Correct Answer: 1 kg

Q29. Convert 250 micrograms (μg) to milligrams (mg):

• 0.025 mg
• 0.25 mg
• 2.5 mg
• 25 mg

Correct Answer: 0.25 mg

Q30. Convert 7.5 mL to fluid drams (approximate):

• 1 fl dram
• 1.5 fl drams
• 2 fl drams
• 3 fl drams

Correct Answer: 2 fl drams

Download