Tests for resins MCQs With Answer

Tests for resins MCQs With Answer

Resins are important pharmaceutical excipients and active natural products; understanding their identification and evaluation is essential for B. Pharm students. This introduction covers common tests for resins including solubility tests, qualitative reactions (e.g., ferric chloride for phenolic resins), physicochemical assays such as acid value, iodine value and softening point, and instrumental methods like TLC and IR spectroscopy for functional group analysis. Emphasis is on pharmaceutical resins, resin identification tests, purity checks, limit tests (ash, loss on drying) and application-relevant properties. Simple, practical and exam-oriented, these MCQs will reinforce concepts and analytical approaches. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. Which of the following is a characteristic solubility property of most natural resins?

• Soluble in water
• Soluble in organic solvents like alcohol and chloroform
• Insoluble in chloroform but soluble in water
• Only soluble in dilute acids

Correct Answer: Soluble in organic solvents like alcohol and chloroform

Q2. The acid value of a resin helps to quantify:

• The degree of unsaturation in the resin
• The amount of volatile oils in the resin
• The free acidic components (resin acids) in the resin
• The inorganic ash content

Correct Answer: The free acidic components (resin acids) in the resin

Q3. Which instrumental method is most useful for identifying functional groups such as carboxylic acids and phenolic OH in resins?

• UV-Visible spectroscopy
• Infrared (IR) spectroscopy
• Flame photometry
• Polarimetry

Correct Answer: Infrared (IR) spectroscopy

Q4. The iodine value of a resin provides information about:

• The molecular weight distribution
• The degree of unsaturation (double bonds)
• The water solubility
• The presence of aromatic rings

Correct Answer: The degree of unsaturation (double bonds)

Q5. Ferric chloride test is used in resin analysis to detect:

• Carboxylic acids specifically
• Phenolic hydroxyl groups
• Aliphatic hydrocarbons
• Neutral sugars

Correct Answer: Phenolic hydroxyl groups

Q6. Loss on drying for a resin sample primarily measures:

• The volatile oil content
• The fixed oil content
• The inorganic residue after burning
• Moisture and volatile matter

Correct Answer: Moisture and volatile matter

Q7. Which of the following is a major natural resin obtained from pine and used in pharmaceuticals as rosin?

• Colophony
• Shellac
• Myrrh
• Frankincense

Correct Answer: Colophony

Q8. Softening point is an important physical test for which type of resin property?

• Chemical composition
• Thermal and mechanical behavior (temperature at which resin softens)
• pH of resin solution
• Degree of polymerization only

Correct Answer: Thermal and mechanical behavior (temperature at which resin softens)

Q9. Thin-layer chromatography (TLC) in resin analysis is primarily used to:

• Measure ash content
• Separate and identify components or impurities
• Determine acid value
• Quantify moisture

Correct Answer: Separate and identify components or impurities

Q10. Which test would best detect inorganic contamination in a resin sample?

• Acid value
• Ash content determination
• Iodine value
• Ferric chloride test

Correct Answer: Ash content determination

Q11. In the context of resin analysis, a high iodine value indicates:

• High aromatic content
• High degree of unsaturation (many double bonds)
• High acid content
• Low molecular weight

Correct Answer: High degree of unsaturation (many double bonds)

Q12. Which of the following tests is quantitative and measures the amount of free acid groups in a resin sample?

• Ferric chloride test
• Acid value determination (titration)
• Solubility test in ethanol
• Flame test

Correct Answer: Acid value determination (titration)

Q13. A resin that gives a purple or blue color with ferric chloride likely contains which type of moiety?

• Alkyl chains only
• Phenolic groups
• Saturated hydrocarbons
• Nitrogen-containing bases

Correct Answer: Phenolic groups

Q14. Which technique can provide molecular-level identification of individual resin components and volatile constituents?

• Gas chromatography–mass spectrometry (GC-MS)
• Simple solubility test
• Loss on drying
• Ash content

Correct Answer: Gas chromatography–mass spectrometry (GC-MS)

Q15. For pharmaceutical resins used in coatings, which property is most critical to evaluate?

• Color only
• Film-forming ability and softening point
• Inorganic ash alone
• Scent profile

Correct Answer: Film-forming ability and softening point

Q16. Which qualitative test would indicate the presence of resin acids in rosin?

• Ferric chloride gives green color
• Extraction into alkali followed by acidification (salification and precipitation)
• Loss on drying >20%
• High iodine value only

Correct Answer: Extraction into alkali followed by acidification (salification and precipitation)

Q17. Why is infrared spectroscopy preferred for confirming carboxylic acid groups in resins?

• Because it measures boiling point directly
• Because carboxylic acids show characteristic C=O and O–H bands
• Because it quantifies ash content
• Because it gives elemental composition

Correct Answer: Because carboxylic acids show characteristic C=O and O–H bands

Q18. Saponification value is most relevant for which type of resin-containing material?

• Pure hydrocarbon resins
• Resin samples containing esterified components or fatty esters
• Inorganic resins
• Highly crosslinked thermoset resins only

Correct Answer: Resin samples containing esterified components or fatty esters

Q19. A resin giving a dark, sooty flame and aromatic odor on ignition suggests presence of:

• Highly volatile inorganic salts
• Unsaturated aromatic constituents and high carbon content
• High water content
• Purely aliphatic saturated hydrocarbons

Correct Answer: Unsaturated aromatic constituents and high carbon content

Q20. Which parameter is used to assess the presence of volatile components in a resin sample?

• Acid value
• Loss on drying or distillation of volatile matter
• Ash value
• Iodine value

Correct Answer: Loss on drying or distillation of volatile matter

Q21. In pharmaceutical analysis, why is TLC run for resin samples often visualized under UV or after derivatization?

• Resins are always colorless and invisible otherwise
• To detect and differentiate components by UV absorption or colored derivatives
• To measure acid value directly on the plate
• Because TLC cannot separate resin components without UV light

Correct Answer: To detect and differentiate components by UV absorption or colored derivatives

Q22. Which of the following is NOT a common pharmaceutical test for resins?

• Iodine value
• Acid value
• Loss on drying
• Cholera agglutination test

Correct Answer: Cholera agglutination test

Q23. The presence of polymerized or oxidized material in a resin sample would most likely affect which measured property?

• Softening point and color
• Only the ash content
• Acid value will drop to zero always
• UV absorption becomes zero

Correct Answer: Softening point and color

Q24. Which test would help detect adulteration of a pharmaceutical coating resin with cheaper natural gums?

• TLC fingerprinting and solubility comparison
• Measurement of iodine value only
• Flame test only
• Determination of pH of resin solution solely

Correct Answer: TLC fingerprinting and solubility comparison

Q25. Which analytical method provides a rapid fingerprint of conjugated chromophores in resins?

• IR spectroscopy
• UV-Visible spectroscopy
• Ash content
• Softening point

Correct Answer: UV-Visible spectroscopy

Q26. For resins rich in phenolic structures, which reagent besides ferric chloride can give characteristic color reactions?

• Sodium chloride solution
• Lead acetate (formation of colored complexes or precipitates with some phenolics)
• Silver nitrate only for halides
• Fehling’s solution

Correct Answer: Lead acetate (formation of colored complexes or precipitates with some phenolics)

Q27. Standardization of a pharmaceutical resin used as an excipient commonly includes which of the following tests?

• Microbiological agar diffusion only
• Physical characteristics (softening point), purity (ash, loss on drying), acid/iodine values
• Only sensory evaluation (odor and taste)
• Only boiling point determination

Correct Answer: Physical characteristics (softening point), purity (ash, loss on drying), acid/iodine values

Q28. Which sample preparation step is often required before running IR on a resin?

• Neutralization with strong base always
• Preparation of KBr pellet or thin film from solution for IR analysis
• Dilution with water and freeze-drying
• Combustion to ash

Correct Answer: Preparation of KBr pellet or thin film from solution for IR analysis

Q29. A low acid value in a resin sample may indicate:

• High content of free resin acids
• Neutralization, esterification or absence of free acid groups
• Excess moisture
• High iodine value always

Correct Answer: Neutralization, esterification or absence of free acid groups

Q30. Which of the following best describes why resins are evaluated for ash content in pharmaceutical analysis?

• To determine the degree of unsaturation
• To estimate inorganic adulterants or residual inorganic contamination after burning
• To measure phenolic content directly
• To assess molecular weight distribution

Correct Answer: To estimate inorganic adulterants or residual inorganic contamination after burning

G S Sachin

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.

Mail- Sachin@pharmacyfreak.com