Structure and uses of tartaric acid MCQs With Answer

Introduction: Tartaric acid is a dicarboxylic, dihydroxy organic acid whose structure and pharmaceutical applications are essential for B. Pharm students studying excipients, salt formation and stereochemistry. This compound (IUPAC: 2,3-dihydroxybutanedioic acid) contains two carboxyl and two hydroxyl groups, two stereocenters, and exists as enantiomers and a meso form. Key topics include molecular formula, pKa values, tartrate salts (e.g., morphine tartrate), role as an acidulant in effervescents, and use as a chiral resolving agent in drug purification. Mastery of the structure and uses of tartaric acid MCQs With Answer will boost formulation and medicinal chemistry knowledge. Now let’s test your knowledge with 50 MCQs on this topic.

Q1. What is the IUPAC name of tartaric acid?

• 2,3-Dihydroxybutanedioic acid
• 2,4-Dihydroxybutanoic acid
• 3,4-Dihydroxybutanedioic acid
• 2-Hydroxybutanedioic acid

Correct Answer: 2,3-Dihydroxybutanedioic acid

Q2. What is the molecular formula of tartaric acid?

• C3H4O6
• C4H6O6
• C4H8O6
• C5H8O6

Correct Answer: C4H6O6

Q3. How many stereoisomers does tartaric acid have?

• 2
• 3
• 4
• 1

Correct Answer: 3

Q4. Which functional groups are present in tartaric acid?

• Two aldehyde groups
• Two carboxyl and two hydroxyl groups
• One ketone and one alcohol group
• Two amine groups

Correct Answer: Two carboxyl and two hydroxyl groups

Q5. Which form of tartaric acid is optically inactive despite having stereocenters?

• L-(+)-tartaric acid
• D-(-)-tartaric acid
• Meso-tartaric acid
• Racemic tartaric acid

Correct Answer: Meso-tartaric acid

Q6. Which statement about natural occurrence is correct?

• Tartaric acid is rarely found in nature
• L-(+)-tartaric acid is the naturally occurring enantiomer
• D-(-)-tartaric acid is the common natural form
• Meso-tartaric acid is abundant in fruits

Correct Answer: L-(+)-tartaric acid is the naturally occurring enantiomer

Q7. What is the approximate molecular weight of tartaric acid?

• 90 g/mol
• 150 g/mol
• 180 g/mol
• 120 g/mol

Correct Answer: 150 g/mol

Q8. Which of the following is a common salt of tartaric acid found in winemaking and pharmaceuticals?

• Calcium sulfate
• Potassium hydrogen tartrate (cream of tartar)
• Sodium chloride
• Magnesium carbonate

Correct Answer: Potassium hydrogen tartrate (cream of tartar)

Q9. Tartaric acid is classified chemically as:

• A monocarboxylic acid
• An amino acid
• A dicarboxylic acid
• An inorganic acid

Correct Answer: A dicarboxylic acid

Q10. Typical pKa1 value (first dissociation) for tartaric acid is closest to:

• 0.5
• 2.98
• 7.0
• 10.5

Correct Answer: 2.98

Q11. Typical pKa2 value (second dissociation) for tartaric acid is closest to:

• 1.2
• 3.0
• 4.34
• 6.8

Correct Answer: 4.34

Q12. In effervescent formulations tartaric acid is primarily used to:

• Act as a lubricant
• React with bicarbonate to release CO2
• Serve as a preservative
• Act as an emulsifier

Correct Answer: React with bicarbonate to release CO2

Q13. Which property makes tartaric acid useful as a chiral resolving agent?

• High volatility
• Ability to form diastereomeric salts with racemates
• Strong reducing power
• High melting point

Correct Answer: Ability to form diastereomeric salts with racemates

Q14. Which of the following drug salts is commonly formed using tartaric acid?

• Morphine tartrate
• Aspirin tartrate
• Paracetamol tartrate

Correct Answer: Morphine tartrate

Q15. The presence of two stereogenic centers in tartaric acid means it could theoretically have how many stereochemical configurations?

• 2
• 3
• 4
• 1

Correct Answer: 4

Q16. Why does tartaric acid show only three distinct stereoisomers instead of four?

• Because one configuration is unstable
• Because two configurations are identical due to an internal plane of symmetry (meso form)
• Because one stereocenter is not chiral
• Because one isomer decomposes rapidly

Correct Answer: Because two configurations are identical due to an internal plane of symmetry (meso form)

Q17. The IUPAC structural descriptor indicates tartaric acid is a butanedioic derivative; which carbon skeleton length does this imply?

• Two-carbon skeleton
• Three-carbon skeleton
• Four-carbon skeleton
• Five-carbon skeleton

Correct Answer: Four-carbon skeleton

Q18. Which of the following is a pharmaceutical application of tartaric acid beyond effervescence?

• As a primary active analgesic
• As an acidulant and pH adjuster in syrups
• As a topical anesthetic
• As an anti-infective agent

Correct Answer: As an acidulant and pH adjuster in syrups

Q19. Cream of tartar chemically corresponds to which ion form of tartaric acid?

• Free tartaric acid
• Potassium hydrogen tartrate
• Sodium tartrate
• Calcium tartrate

Correct Answer: Potassium hydrogen tartrate

Q20. Which statement about meso-tartaric acid is true?

• It is optically active and dextrorotatory
• It is optically inactive due to internal compensation
• It is the most commonly used resolving agent
• It has three stereocenters

Correct Answer: It is optically inactive due to internal compensation

Q21. For buffer preparation around pH 3–4, tartaric acid is suitable because:

• Its pKa values fall in this range
• It has basic properties
• It is insoluble in water
• It is a strong oxidizing agent

Correct Answer: Its pKa values fall in this range

Q22. Which stereochemical concept explains why two enantiomers rotate plane-polarized light in opposite directions?

• The presence of a meso form
• Chirality of stereogenic centers
• Acidity of carboxyl groups
• Formation of salts

Correct Answer: Chirality of stereogenic centers

Q23. Which analytical technique is commonly used to distinguish enantiomers of tartaric acid derivatives?

• Achiral gas chromatography
• Polarimetry or chiral HPLC
• Infrared spectroscopy only
• Simple UV-Vis without derivatization

Correct Answer: Polarimetry or chiral HPLC

Q24. Which derivative of tartaric acid is frequently used to resolve racemic amines or alcohols?

• Tartrate esters producing diastereomeric salts
• Oxalate esters
• Nitrate salts
• Chloride salts

Correct Answer: Tartrate esters producing diastereomeric salts

Q25. Tartaric acid forms stable complexes with metal ions; this chelating ability is mainly due to:

• Its aromatic ring
• Multiple coordinating oxygen atoms from hydroxyl and carboxyl groups
• Its sulfur atoms
• Its amine groups

Correct Answer: Multiple coordinating oxygen atoms from hydroxyl and carboxyl groups

Q26. Which product results when tartaric acid reacts stoichiometrically with sodium hydroxide?

• Potassium hydrogen tartrate
• Sodium tartrate salts
• Free carbon dioxide only
• Chloroform

Correct Answer: Sodium tartrate salts

Q27. In pharmaceutical crystallization, tartrate formation is used predominantly to:

• Increase volatility of actives
• Modify solubility and aid purification of drugs
• Color formulations
• Reduce molecular weight

Correct Answer: Modify solubility and aid purification of drugs

Q28. Which statement about optical rotation of tartaric acid enantiomers is correct?

• Enantiomers have identical optical rotation values and directions
• Enantiomers rotate plane-polarized light equally but in opposite directions
• Only racemic tartaric acid is optically active
• Meso-tartaric acid shows the largest rotation

Correct Answer: Enantiomers rotate plane-polarized light equally but in opposite directions

Q29. Which of the following is NOT a pharmaceutical use of tartaric acid?

• Effervescent tablet component
• Chiral resolving agent
• Primary active antiviral agent
• Acidulant in syrups

Correct Answer: Primary active antiviral agent

Q30. The ability of tartaric acid to form tartrate salts with alkaloids is exploited mainly for:

• Masking odor of alkaloids
• Isolation and purification of alkaloids as crystalline salts
• Making alkaloids volatile
• Neutralizing basic excipients only

Correct Answer: Isolation and purification of alkaloids as crystalline salts

Q31. Which of the following is a common laboratory test to detect tartaric acid presence in a solution?

• Silver mirror test
• Formation of potassium hydrogen tartrate precipitate on cooling
• Formation of a blue complex with copper sulfate without reagent
• Ammonia smell on heating

Correct Answer: Formation of potassium hydrogen tartrate precipitate on cooling

Q32. In the naming convention, “tartrate” refers to:

• Any sulfate salt
• Salts or esters derived from tartaric acid
• Only the potassium salt
• An oxidized form of tartaric acid

Correct Answer: Salts or esters derived from tartaric acid

Q33. Which property of tartaric acid influences its use in taste masking for oral liquids?

• Sweetness similar to sucrose
• Acidic taste that balances sweetness
• Bitter taste that improves palatability
• No taste at all

Correct Answer: Acidic taste that balances sweetness

Q34. Which is a common inorganic counter-ion used to form tartrate salts for pharmaceuticals?

• Chloride
• Potassium or sodium
• Peroxide
• Nitrite

Correct Answer: Potassium or sodium

Q35. Tartaric acid’s two hydroxyl groups are located on adjacent carbons; this makes it a:

• Vicinal diol
• Glycolic acid derivative
• Terminal alcohol
• Polyene

Correct Answer: Vicinal diol

Q36. Which statement about racemic tartaric acid (DL-tartaric acid) is correct?

• It consists of an equal mixture of enantiomers and is optically inactive
• It is identical to meso-tartaric acid
• It is more optically active than pure enantiomers
• It cannot form salts

Correct Answer: It consists of an equal mixture of enantiomers and is optically inactive

Q37. Which synthetic application uses tartaric acid derivatives frequently in asymmetric synthesis?

• As oxidizing agents only
• As chiral auxiliaries or resolving agents to induce stereochemistry
• To increase acidity of bases
• As radical initiators

Correct Answer: As chiral auxiliaries or resolving agents to induce stereochemistry

Q38. Which statement best describes the solubility of tartaric acid?

• Insoluble in water, soluble in nonpolar solvents
• Highly soluble in water and miscible with polar solvents like glycerol
• Only soluble in concentrated acids
• Only sparingly soluble in all solvents

Correct Answer: Highly soluble in water and miscible with polar solvents like glycerol

Q39. Which of the following is a reason to choose a tartrate salt of a drug in formulation?

• To lower pH to 1–2 permanently
• To improve crystallinity and stability or modify solubility
• To make the compound volatile
• To confer basicity to an acidic drug

Correct Answer: To improve crystallinity and stability or modify solubility

Q40. Which reaction occurs when tartaric acid is heated strongly?

• It sublimes unchanged at low temperature
• It dehydrates and can decompose on strong heating
• It converts into an alkane
• It polymerizes into a stable resin

Correct Answer: It dehydrates and can decompose on strong heating

Q41. Which technique is commonly used to prepare tartrate salts of basic drugs?

• Neutralize the base with tartaric acid to form the tartrate salt
• Oxidize the base with tartaric acid
• Reduce the base with tartaric acid
• Heat the base with sulfuric acid only

Correct Answer: Neutralize the base with tartaric acid to form the tartrate salt

Q42. Tartaric acid’s role in buffer systems is mainly due to:

• High ionic strength only
• Two dissociable protons with distinct pKa values
• Its ability to chelate only
• Being a non-ionizable compound

Correct Answer: Two dissociable protons with distinct pKa values

Q43. Which statement about tartrate esters is correct?

• They cannot be formed from tartaric acid
• They are useful as chiral derivatizing agents in analysis
• They are always racemic
• They are inert and have no stereochemical influence

Correct Answer: They are useful as chiral derivatizing agents in analysis

Q44. Which of the following is a true example of a tartrate salt used pharmaceutically?

• Quinine sulfate
• Ephedrine tartrate
• Ibuprofen sodium
• Acetaminophen phosphate

Correct Answer: Ephedrine tartrate

Q45. Tartaric acid contributes to the stability of certain formulations by:

• Acting as a strong base
• Adjusting pH and chelating metal impurities
• Increasing microbial growth
• Converting APIs into volatile forms

Correct Answer: Adjusting pH and chelating metal impurities

Q46. When resolving a racemic amine, which outcome is expected upon forming tartrate salts?

• Formation of identical salts for both enantiomers
• Formation of diastereomeric salts with different solubilities enabling separation
• No salt formation occurs
• Complete racemization to meso compound

Correct Answer: Formation of diastereomeric salts with different solubilities enabling separation

Q47. Which structural feature distinguishes meso-tartaric acid from its enantiomers?

• Lack of hydroxyl groups
• Internal plane of symmetry resulting in achirality
• Extra carbon atom
• Presence of a sulfur atom

Correct Answer: Internal plane of symmetry resulting in achirality

Q48. In storage of tartaric acid-containing solutions, precipitation of potassium hydrogen tartrate can occur due to:

• Decrease in temperature leading to decreased solubility
• Increase in pH making everything more soluble
• Exposure to light creating tartrate gas
• Complete conversion to meso form

Correct Answer: Decrease in temperature leading to decreased solubility

Q49. Which chemical name is synonymous with tartaric acid?

• Ethanedioic acid
• 2,3-Dihydroxybutanedioic acid
• Propane-1,2,3-triol
• Benzene-1,2-diol

Correct Answer: 2,3-Dihydroxybutanedioic acid

Q50. For a B. Pharm student, mastering tartaric acid is important because it directly relates to:

• Clinical diagnostics only
• Formulation design, salt selection, stereochemistry and drug purification techniques
• Only pharmacokinetics calculations
• Only sterile manufacturing conditions

Correct Answer: Formulation design, salt selection, stereochemistry and drug purification techniques

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.

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