Physical evaluation of crude drugs involves systematic assessment of measurable and observable properties — organoleptic characters, microscopic features, moisture content, ash values, extractive values, swelling and foaming indices, particle size and bulk density. For B. Pharm students this topic builds essential skills in quality control, authenticity testing and detection of adulteration of herbal materials. Understanding tests such as loss on drying, acid-insoluble ash, alcohol- and water-soluble extractives, refractive index and powder microscopy helps relate laboratory findings to therapeutic efficacy and safety. These MCQs emphasize practical interpretation, standard procedures and calculation-based reasoning to strengthen your pharmacognosy and pharmaceutics foundations. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. Which parameter is NOT considered an organoleptic characteristic during physical evaluation of crude drugs?
- Color
- Odor
- Taste
- Refractive index
Correct Answer: Refractive index
Q2. Which test specifically detects and quantifies extraneous plant parts and debris in a bulk sample?
- Ash value determination
- Foreign matter test
- Loss on drying
- Extractive value
Correct Answer: Foreign matter test
Q3. Acid-insoluble ash is mainly used to estimate contamination by which material?
- Alkali salts
- Silica and siliceous matter
- Oxalates
- Organic residues
Correct Answer: Silica and siliceous matter
Q4. Loss on drying primarily measures which property of a crude drug?
- Volatile oil content
- Moisture content
- Total ash
- Extractive value
Correct Answer: Moisture content
Q5. The extractive value of a crude drug indicates:
- The amount of inorganic ash present
- The total volatile constituents lost on drying
- The proportion of constituents soluble in a specified solvent
- The bulk density of the powdered drug
Correct Answer: The proportion of constituents soluble in a specified solvent
Q6. Swelling index is an important physical test used to estimate the content of which class of constituents?
- Alkaloids
- Tannins
- Mucilage and polysaccharides
- Saponins
Correct Answer: Mucilage and polysaccharides
Q7. Foaming index is routinely used to detect the presence of which phytochemical group?
- Flavonoids
- Saponins
- Terpenes
- Glycosides
Correct Answer: Saponins
Q8. Powder microscopy assists physical evaluation by revealing:
- Quantitative ash content
- Microscopic diagnostic characters like trichomes, stomata and vessel elements
- Refractive index of oils
- Extractive value in solvents
Correct Answer: Microscopic diagnostic characters like trichomes, stomata and vessel elements
Q9. Sieve analysis provides direct information about which physical property of powdered crude drugs?
- Chemical composition
- Particle size distribution
- Loss on drying
- Acid-insoluble ash
Correct Answer: Particle size distribution
Q10. Which physical parameter is commonly measured to characterize essential oils and fixed oils?
- Foaming index
- Swelling index
- Refractive index
- Water-soluble ash
Correct Answer: Refractive index
Q11. Water-soluble ash primarily estimates the proportion of:
- Siliceous impurities
- Water-soluble inorganic matter
- Volatile organic compounds
- Glycosidic constituents
Correct Answer: Water-soluble inorganic matter
Q12. Standard loss on drying (LOD) for many crude drug determinations is performed by heating the sample at approximately:
- 60 °C
- 80 °C
- 105 °C
- 150 °C
Correct Answer: 105 °C
Q13. Which extractive value would you determine using 90% ethanol as the solvent?
- Alcohol soluble extractive
- Water soluble extractive
- Total ash
- Acid-insoluble ash
Correct Answer: Alcohol soluble extractive
Q14. A high swelling index in a powdered drug indicates:
- High volatile oil content
- Significant mucilage or gel-forming polysaccharides
- Excess silica contamination
- High saponin content
Correct Answer: Significant mucilage or gel-forming polysaccharides
Q15. Which of the following is NOT part of routine physical evaluation of crude drugs?
- Organoleptic examination
- Ash value determination
- TLC fingerprinting
- Powder microscopy
Correct Answer: TLC fingerprinting
Q16. Bulk density and tapped density measurements are used to calculate:
- Loss on drying
- Extractive value
- Carr’s compressibility index (flow property)
- Foaming index
Correct Answer: Carr’s compressibility index (flow property)
Q17. Which physical test would most quickly indicate microbial susceptibility due to a crude drug’s storage condition?
- Acid-insoluble ash
- Loss on drying (high moisture)
- Refractive index
- Particle size distribution
Correct Answer: Loss on drying (high moisture)
Q18. Powdered drug adulteration such as addition of sand or silica would most directly increase which parameter?
- Total ash and acid-insoluble ash
- Alcohol-soluble extractive
- Swelling index
- Foaming index
Correct Answer: Total ash and acid-insoluble ash
Q19. The process to obtain acid-insoluble ash involves:
- Treating the sample with water and evaporating
- Incinerating to total ash then treating with dilute hydrochloric acid and collecting insoluble residue
- Measuring weight loss on drying at 40 °C
- Macerating with alcohol and evaporating the solvent
Correct Answer: Incinerating to total ash then treating with dilute hydrochloric acid and collecting insoluble residue
Q20. Extractive value of a crude drug is typically expressed as:
- mg per mL of solvent
- Percentage w/w of the air-dried drug
- pH units
- Relative density
Correct Answer: Percentage w/w of the air-dried drug
Q21. Which technique is most informative for detecting morphological adulteration in a powdered herbal drug?
- Gas chromatography
- Powder microscopy
- Refractive index measurement
- Foaming index
Correct Answer: Powder microscopy
Q22. Which physical test is most useful for preliminary screening of saponin-rich drugs?
- Swelling index
- Foaming index
- Acid-insoluble ash
- Refractive index
Correct Answer: Foaming index
Q23. The presence of high water-soluble extractive value relative to alcohol-soluble extractive suggests:
- Predominantly polar constituents like sugars and salts
- Predominantly non-polar terpenes
- High silica contamination
- High volatile oil content
Correct Answer: Predominantly polar constituents like sugars and salts
Q24. Which measurement helps assess flow properties and packing behavior of powdered crude drugs for formulation?
- Refractive index
- Bulk and tapped density
- Acid-insoluble ash
- Foaming index
Correct Answer: Bulk and tapped density
Q25. Determination of refractive index in oils helps to detect:
- Presence of mucilage
- Adulteration and quality variations in fixed and essential oils
- Total ash content
- Foaming capacity
Correct Answer: Adulteration and quality variations in fixed and essential oils
Q26. Which of the following best describes the purpose of ash value determinations?
- To quantify volatile constituents
- To assess inorganic residue and evaluate contamination or purity
- To determine the drug’s refractive index
- To measure saponin content
Correct Answer: To assess inorganic residue and evaluate contamination or purity
Q27. A sample with unusually low alcohol-soluble extractive but normal total ash likely indicates:
- High volatile oil content
- Loss of alcohol-soluble phytoconstituents due to improper drying or storage
- Siliceous contamination
- Excess moisture
Correct Answer: Loss of alcohol-soluble phytoconstituents due to improper drying or storage
Q28. Which of the following is a direct indicator of siliceous contamination in crude drugs?
- High water-soluble ash
- High acid-insoluble ash
- Low extractive value
- Low swelling index
Correct Answer: High acid-insoluble ash
Q29. Which standard analytical step helps differentiate between volatile loss and hygroscopic moisture when determining LOD?
- Using titration after drying
- Drying at controlled temperature (e.g., 105 °C) until constant weight
- Measuring refractive index before and after drying
- Performing powder microscopy
Correct Answer: Drying at controlled temperature (e.g., 105 °C) until constant weight
Q30. Carr’s index is calculated from bulk and tapped density to evaluate which property of powdered crude drugs?
- Chemical purity
- Flowability and compressibility
- Moisture content
- Acid-insoluble ash content
Correct Answer: Flowability and compressibility
I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.
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