Resins – Colophony MCQs With Answer

Resins – Colophony MCQs With Answer

Resins such as colophony (rosin) are natural pine-derived materials rich in resin acids like abietic acid. For B.Pharm students, understanding their physicochemical properties, identification tests, compendial standards, pharmaceutical excipients roles (adhesives, plasters, emulsifiers), and safety concerns (contact dermatitis, oxidation) is essential. This set goes deeper into composition, chemical reactions (saponification, esterification, polymerization), analytical assays (acid value), and formulation uses—linking theory to practical pharmaceutical applications and quality control. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. What is colophony commonly known as in pharmaceutical and industrial contexts?

• Turpentine
• Rosin
• Pitch
• Gum benzoin

Correct Answer: Rosin

Q2. Colophony is primarily obtained from which plant source?

• Citrus peel exudates
• Pinus (pine) species
• Ficus latex
• Boswellia trees

Correct Answer: Pinus (pine) species

Q3. Which class of compounds constitutes the major chemical components of colophony?

• Monoterpenes
• Diterpenoid resin acids
• Alkaloids
• Polysaccharides

Correct Answer: Diterpenoid resin acids

Q4. Which specific resin acid is most associated with colophony chemistry and allergenicity?

• Salicylic acid
• Abietic acid
• Oleic acid
• Ascorbic acid

Correct Answer: Abietic acid

Q5. Which statement correctly describes the solubility of colophony?

• Freely soluble in water
• Insoluble in organic solvents like ethanol and ether
• Insoluble in water but soluble in organic solvents (ethanol, ether, chloroform)
• Soluble in strong acids only

Correct Answer: Insoluble in water but soluble in organic solvents (ethanol, ether, chloroform)

Q6. What typical melting or softening range is associated with common rosin (colophony)?

• 20–30 °C
• 40–50 °C
• 70–80 °C
• 120–140 °C

Correct Answer: 70–80 °C

Q7. Which pharmacopeial parameter is commonly used to assess the free resin acids in colophony?

• Acid value (mg KOH/g)
• Viscosity at 25 °C
• Optical rotation
• Water content by Karl Fischer

Correct Answer: Acid value (mg KOH/g)

Q8. Which pharmaceutical application best illustrates the use of colophony as an excipient?

• Enteric coating polymer
• Adhesive component in medicated plasters and transdermal patches
• Primary binder in tablet cores for immediate release
• Preservative for injectables

Correct Answer: Adhesive component in medicated plasters and transdermal patches

Q9. What chemical reaction converts colophony into more water-dispersible emulsifying agents?

• Nitration
• Hydrogenation
• Esterification to produce glycerol esters (rosin glyceryl esters)
• Carboxylation

Correct Answer: Esterification to produce glycerol esters (rosin glyceryl esters)

Q10. Exposure to colophony can cause which adverse reaction relevant to pharmacists and formulators?

• Severe systemic toxicity after dermal contact
• Immediate anaphylaxis in all patients
• Contact dermatitis and allergic sensitization
• Renal failure with topical use

Correct Answer: Contact dermatitis and allergic sensitization

Q11. The process used to remove volatile turpentine from crude pine resin to yield colophony is:

• Steam distillation or fractional distillation
• Solvent precipitation with water
• Cold pressing
• Enzymatic hydrolysis

Correct Answer: Steam distillation or fractional distillation

Q12. Which functional group is prominent in resin acids and is responsible for titratable acidity?

• Alcohol (–OH)
• Carboxylic acid (–COOH)
• Aldehyde (–CHO)
• Ester (–COOR)

Correct Answer: Carboxylic acid (–COOH)

Q13. Which analytical technique is most useful for characterizing resin acid composition in detailed research studies?

• UV-Vis spectrophotometry
• Gas chromatography–mass spectrometry (GC-MS) after derivatization
• Paper chromatography only
• Flame photometry

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

Q14. Heating or polymerization of colophony is performed industrially to:

• Lower melting point and reduce tack
• Improve thermal stability and increase softening point and tack for adhesives
• Convert it into water-soluble monomers
• Remove all resin acids

Correct Answer: Improve thermal stability and increase softening point and tack for adhesives

Q15. Which statement about rosin soap formation is correct?

• Rosin acids are esterified directly to form soaps
• Rosin acids react with alkali (NaOH) to form resin soaps (salts of resin acids)
• Rosin does not react with bases
• Rosin forms soaps only with ammonium but not sodium

Correct Answer: Rosin acids react with alkali (NaOH) to form resin soaps (salts of resin acids)

Q16. Which of the following is NOT a typical component of crude pine resin?

• Volatile terpenes (turpentine)
• Rosin (colophony)
• Resin acids
• High levels of polysaccharide starch

Correct Answer: High levels of polysaccharide starch

Q17. Which derivative of colophony is widely used to improve varnish adhesion and film formation in coatings?

• Rosin esters and polymerized rosin
• Sodium rosinate only
• Rosin hydrocarbons after decarboxylation
• Rosin siloxanes

Correct Answer: Rosin esters and polymerized rosin

Q18. In pharmaceutical formulation, glyceryl esters of rosin are primarily used as:

• Antimicrobial preservatives
• Plasticizers for capsules
• Emulsifying agents and tackifiers in topical systems
• pH adjusters in solutions

Correct Answer: Emulsifying agents and tackifiers in topical systems

Q19. Which of the following tests is commonly used to detect volatile matter in a rosin sample?

• Loss on drying at 105 °C only
• Determination of volatile matter by heating under specified conditions to remove turpentine
• Colorimetric assay for pigments
• Melting point alone

Correct Answer: Determination of volatile matter by heating under specified conditions to remove turpentine

Q20. Which property of colophony is most responsible for its use in pressure-sensitive adhesives?

• High water solubility
• Oxidative fragility
• Tackiness and softening point modifiable by formulation
• Strong basicity

Correct Answer: Tackiness and softening point modifiable by formulation

Q21. Hydrogenation of resin acids in colophony is carried out industrially to:

• Increase unsaturation and allergenicity
• Reduce double bonds, decreasing tendency to oxidize and reducing allergenicity
• Convert rosin into volatile monoterpenes
• Increase acidity dramatically

Correct Answer: Reduce double bonds, decreasing tendency to oxidize and reducing allergenicity

Q22. Which volatile constituent is removed from crude resin to produce colophony and is chiefly responsible for pine odor?

• Alpha-pinene (turpentine constituents)
• Abietic acid
• Squalene
• Benzoic acid

Correct Answer: Alpha-pinene (turpentine constituents)

Q23. Which storage condition is most appropriate to minimize deterioration of colophony?

• Hot, humid environment with sunlight exposure
• Cool, dry, airtight container away from oxidants
• Open containers near strong bases
• Submerged in water

Correct Answer: Cool, dry, airtight container away from oxidants

Q24. Which compendial monograph title corresponds to colophony in many pharmacopoeias?

• Gum Turpentine
• Colophony (Rosin)
• Beeswax
• Gum Arabic

Correct Answer: Colophony (Rosin)

Q25. A correct statement about the acid value of rosin is:

• It measures basic impurities
• It is unrelated to resin acidity
• It quantifies the milligrams of KOH required to neutralize free acids per gram of sample
• It measures water content

Correct Answer: It quantifies the milligrams of KOH required to neutralize free acids per gram of sample

Q26. Which reaction would you expect if colophony is treated with excess methanol and an acid catalyst?

• Oxidative cleavage to small acids
• Esterification of resin acids to form methyl esters
• Complete dissolution in water
• Polymerization to cellulose-like polymers

Correct Answer: Esterification of resin acids to form methyl esters

Q27. Which of the following is a common quality-control concern for pharmaceutical-grade colophony?

• Microbial count exceeding sterile limits for injectables
• Excess volatile matter (residual turpentine) and inappropriate acid value
• Presence of heavy metals only in aqueous extracts
• Radioactivity

Correct Answer: Excess volatile matter (residual turpentine) and inappropriate acid value

Q28. Which chemical modification of colophony improves compatibility with synthetic polymers in pressure-sensitive adhesive formulations?

• Decarboxylation to remove acid groups
• Conversion to rosin esters or hydrogenated rosin esters
• Removal of all resin acids by saponification and washing
• Addition of strong oxidizers

Correct Answer: Conversion to rosin esters or hydrogenated rosin esters

Q29. Which statement correctly describes the interaction of colophony with alkalis during processing?

• Alkalis have no effect on colophony composition
• Alkalis convert resin acids into soluble resin soaps useful for emulsification
• Alkalis polymerize rosin into insoluble waxes
• Alkalis volatilize rosin components into turpentine

Correct Answer: Alkalis convert resin acids into soluble resin soaps useful for emulsification

Q30. For a B.Pharm student studying pharmacognosy and formulation, which learning outcome is most directly supported by mastering colophony knowledge?

• Understanding of microbial sterile techniques
• Ability to design parenteral nutrition regimens
• Competence in selecting and evaluating natural excipients (physicochemical properties, assays, safety) for topical and adhesive formulations
• Skill in synthesizing peptide therapeutics

Correct Answer: Competence in selecting and evaluating natural excipients (physicochemical properties, assays, safety) for topical and adhesive formulations

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