Introduction: Tetrachloroethylene (perchloroethylene, PCE) is an important chlorinated solvent with the molecular formula C2Cl4; understanding its structure and uses is essential for B. Pharm students. This introduction covers the structure of tetrachloroethylene, key physical and chemical properties, industrial and pharmaceutical-related uses (dry-cleaning, degreasing, extraction), and health, toxicology and environmental concerns. Emphasis is placed on how its electron-withdrawing chlorines influence reactivity, stability and biological fate, and on safe handling and regulatory considerations. These topics are ideal for exam preparation and practical application in pharmaceutical contexts. Now let’s test your knowledge with 50 MCQs on this topic.
Q1. What is the molecular formula of tetrachloroethylene?
- C2Cl4
- C2H2Cl2
- CCl4
- C2Cl6
Correct Answer: C2Cl4
Q2. What is the common IUPAC name for tetrachloroethylene?
- Perchloroethylene
- Tetrachloroethane
- Carbon tetrachloride
- Trichloroethylene
Correct Answer: Perchloroethylene
Q3. Which structural feature characterizes tetrachloroethylene?
- Carbon–carbon double bond with four chlorines attached
- Saturated carbon chain with chlorines on both ends
- Aromatic ring with chlorine substituents
- A carbonyl group bonded to chlorine atoms
Correct Answer: Carbon–carbon double bond with four chlorines attached
Q4. Why is tetrachloroethylene widely used in dry-cleaning?
- High solvency for hydrophobic stains and nonflammability
- Strong oxidizing power to remove stains
- High water solubility for aqueous cleaning
- Biodegradability and nutritional value
Correct Answer: High solvency for hydrophobic stains and nonflammability
Q5. Which physical property is true for tetrachloroethylene at room temperature?
- Colorless, volatile liquid
- Yellow, viscous solid
- Colorless, water-soluble gas
- Brown, flammable oil
Correct Answer: Colorless, volatile liquid
Q6. How would you best describe the polarity of tetrachloroethylene?
- Nonpolar to weakly polar due to symmetric chlorination
- Strongly polar protic solvent
- Highly ionic in nature
- Amphiphilic surfactant
Correct Answer: Nonpolar to weakly polar due to symmetric chlorination
Q7. Which type of laboratory analysis is most appropriate for detecting tetrachloroethylene residues?
- Gas chromatography with mass spectrometry (GC-MS)
- Atomic absorption spectroscopy (AAS)
- pH titration
- UV-visible spectroscopy at 280 nm
Correct Answer: Gas chromatography with mass spectrometry (GC-MS)
Q8. What is the primary reason tetrachloroethylene is preferred over hydrocarbons for some industrial degreasing applications?
- Chemical stability and nonflammability under normal conditions
- Higher flammability for faster drying
- Ability to dissolve water-soluble compounds
- Biodegradability and low cost
Correct Answer: Chemical stability and nonflammability under normal conditions
Q9. Which metabolic organ is most involved in the biotransformation of tetrachloroethylene in humans?
- Liver
- Kidney
- Lung
- Skin
Correct Answer: Liver
Q10. Which metabolic pathway is significant for tetrachloroethylene processing in the body?
- Oxidation by cytochrome P450 leading to chlorinated acids
- Hydrolysis to alcohols by esterases
- Direct conjugation with glucuronic acid only
- Reduction to alkanes by dehydrogenases
Correct Answer: Oxidation by cytochrome P450 leading to chlorinated acids
Q11. Which of the following is a known health effect of acute high-level exposure to tetrachloroethylene?
- CNS depression (dizziness, headache, narcosis)
- Immediate severe hemolysis
- Acute hyperglycemia
- Rapid onset of anaphylaxis
Correct Answer: CNS depression (dizziness, headache, narcosis)
Q12. Tetrachloroethylene is mainly excreted from the human body by which route?
- Exhalation through the lungs
- Fecal elimination
- Salivary secretion
- Excretion only via sweat
Correct Answer: Exhalation through the lungs
Q13. Which environmental concern is most associated with tetrachloroethylene contamination?
- Groundwater contamination due to its persistence and low biodegradability
- Rapid breakdown producing oxygen deficits in water
- Promotion of algal blooms as a nutrient
- Conversion into inert harmless salts
Correct Answer: Groundwater contamination due to its persistence and low biodegradability
Q14. Which spectroscopic technique can confirm the C=C bond in tetrachloroethylene?
- Infrared spectroscopy showing carbon–carbon double-bond features
- NIR indicating strong O–H stretch
- Fluorescence spectroscopy with high emission
- Raman inactive for halogenated alkenes
Correct Answer: Infrared spectroscopy showing carbon–carbon double-bond features
Q15. Which chemical property explains why tetrachloroethylene is a poor substrate for electrophilic addition?
- Strong electron-withdrawing chlorines decrease double-bond reactivity
- High electron density on the double bond favors addition
- Presence of acidic protons on the double bond
- Conjugation with an aromatic ring
Correct Answer: Strong electron-withdrawing chlorines decrease double-bond reactivity
Q16. In pharmaceutical contexts, tetrachloroethylene may be encountered as:
- A solvent or cleaning agent for equipment and glassware
- An active pharmaceutical ingredient for antibiotics
- A preservative in sterile injectables
- A tablet binder
Correct Answer: A solvent or cleaning agent for equipment and glassware
Q17. Which statement about water solubility of tetrachloroethylene is correct?
- Practically insoluble in water
- Completely miscible with water
- Highly soluble and forms hydrates
- Soluble only at high pH
Correct Answer: Practically insoluble in water
Q18. Which feature of tetrachloroethylene affects its environmental transport behavior?
- High volatility and density greater than water
- High biodegradation rate in soil
- Formation of stable ionic species in water
- Strong binding to biodegradable organic matter
Correct Answer: High volatility and density greater than water
Q19. Which occupational safety control is most relevant when working with tetrachloroethylene?
- Local exhaust ventilation and monitoring of airborne levels
- Elimination of oxygen to prevent combustion
- Use of water-based dilution to neutralize vapors
- Mandatory UV light exposure to break vapors down
Correct Answer: Local exhaust ventilation and monitoring of airborne levels
Q20. Which property makes tetrachloroethylene easy to recover and recycle in industrial processes?
- Relatively high boiling point and thermal stability
- Low boiling point and high reactivity
- High miscibility with water for washout recovery
- Immediate biodegradation on contact with air
Correct Answer: Relatively high boiling point and thermal stability
Q21. Which regulatory classification best describes tetrachloroethylene with respect to carcinogenicity?
- Classified as a probable human carcinogen by expert agencies
- Known to be non-carcinogenic in all studies
- Classified as safe for ingestion at any dose
- Classified solely as a nutritional supplement
Correct Answer: Classified as a probable human carcinogen by expert agencies
Q22. Which analytical sample matrix is commonly analyzed for occupational exposure to tetrachloroethylene?
- End-exhaled breath samples
- Hair for vitamin levels
- Salivary glucose levels
- Stool pH
Correct Answer: End-exhaled breath samples
Q23. Which of the following is NOT a typical industrial use of tetrachloroethylene?
- Active ingredient in oral antibiotics
- Metal degreasing cleaner
- Dry-cleaning solvent
- Laboratory extraction solvent
Correct Answer: Active ingredient in oral antibiotics
Q24. Which safety data sheet (SDS) precaution is most likely for tetrachloroethylene?
- Avoid inhalation of vapors and use protective gloves
- Store under direct sunlight to prevent freezing
- Consume to accelerate cleaning
- Mix with oxidizers to improve potency
Correct Answer: Avoid inhalation of vapors and use protective gloves
Q25. What is the primary reason tetrachloroethylene shows low flammability?
- Its high degree of chlorination reduces flammability
- Its high water content prevents burning
- It reacts vigorously with oxygen to extinguish flames
- It is an oxygen-rich compound
Correct Answer: Its high degree of chlorination reduces flammability
Q26. How does tetrachloroethylene typically interact with organic residues on fabrics?
- Dissolves hydrophobic oils and greases effectively
- Hydrolyzes stains into sugars
- Oxidizes fabric fibers to remove color
- Emulsifies proteins to form residue bonds
Correct Answer: Dissolves hydrophobic oils and greases effectively
Q27. In environmental remediation, why are chlorinated solvents like tetrachloroethylene challenging to treat?
- They are dense non-aqueous phase liquids (DNAPLs) that sink in groundwater
- They readily biodegrade into harmless nutrients
- They form stable complexes with iron that are easily filtered
- They evaporate instantly and disappear from contamination zones
Correct Answer: They are dense non-aqueous phase liquids (DNAPLs) that sink in groundwater
Q28. Which statement about chemical reactivity of tetrachloroethylene is accurate?
- Relatively inert to nucleophiles due to electron-withdrawing substituents
- Highly reactive toward nucleophilic addition like aldehydes
- Rapidly polymerizes under mild conditions
- Spontaneously forms peroxides on standing
Correct Answer: Relatively inert to nucleophiles due to electron-withdrawing substituents
Q29. Which disposal method must be considered for tetrachloroethylene-contaminated wastes?
- Specialized hazardous waste treatment and disposal
- Standard municipal sewer disposal as safe practice
- Dilution with water and release to the environment
- Composting with organic kitchen waste
Correct Answer: Specialized hazardous waste treatment and disposal
Q30. Which clinical sign might indicate chronic occupational exposure to tetrachloroethylene?
- Persistent neurological symptoms such as memory impairment
- Immediate severe gastrointestinal bleeding
- Rapid hair growth and hyperpigmentation
- Elevated insulin sensitivity
Correct Answer: Persistent neurological symptoms such as memory impairment
Q31. Which physical constant is approximately correct for tetrachloroethylene?
- Boiling point around 121 °C
- Boiling point near 25 °C
- Boiling point below 0 °C
- Boiling point above 300 °C
Correct Answer: Boiling point around 121 °C
Q32. Which monitoring technique is commonly used to measure workplace air concentrations of tetrachloroethylene?
- Personal air sampling with sorbent tubes and GC analysis
- Urine pH strips on-site
- Colorimetric paper for nitrogen detection
- Tire pressure monitoring
Correct Answer: Personal air sampling with sorbent tubes and GC analysis
Q33. Which functional group is absent in tetrachloroethylene?
- Hydroxyl group (-OH)
- Carbon–carbon double bond
- Chlorine substituents
- Carbon–carbon bond
Correct Answer: Hydroxyl group (-OH)
Q34. Which solvent property is important for tetrachloroethylene’s role in analytical extraction procedures?
- High affinity for nonpolar organic compounds
- Strong hydrogen-bond donating ability
- High polarity to extract salts
- Strong acidity to hydrolyze esters
Correct Answer: High affinity for nonpolar organic compounds
Q35. Why is personal protective equipment (PPE) recommended when handling tetrachloroethylene?
- To prevent skin contact and inhalation of toxic vapors
- Because it causes immediate skin corrosion on contact
- To avoid ingestion due to high nutritional content
- PPE is not necessary for this inert compound
Correct Answer: To prevent skin contact and inhalation of toxic vapors
Q36. Which compound is structurally most similar to tetrachloroethylene?
- Trichloroethylene (similar halogenated alkene)
- Ethyl alcohol (a simple alcohol)
- Acetic acid (a carboxylic acid)
- Glucose (a carbohydrate)
Correct Answer: Trichloroethylene (similar halogenated alkene)
Q37. Which factor decreases the reactivity of the double bond in tetrachloroethylene?
- Electron-withdrawing effect of chlorine atoms
- Electron-donating alkyl substituents
- Conjugation with aromatic system
- Presence of adjacent hydroxyl groups
Correct Answer: Electron-withdrawing effect of chlorine atoms
Q38. For environmental sampling of tetrachloroethylene in groundwater, which property must be considered?
- It can form dense NAPL pools that sink beneath the water table
- It readily mixes uniformly at any concentration with water
- It is neutralized by sunlight in deep aquifers
- It instantly becomes biodegradable in anaerobic aquifers
Correct Answer: It can form dense NAPL pools that sink beneath the water table
Q39. Which waste-management approach reduces release of tetrachloroethylene from dry-cleaning operations?
- Closed-loop solvent recovery systems
- Open-air evaporative tanks to speed dissipation
- Dumping spent solvent into municipal drains
- Mixing spent solvent with bleach and releasing it
Correct Answer: Closed-loop solvent recovery systems
Q40. How does tetrachloroethylene affect the central nervous system on acute exposure?
- Depressant effects, including dizziness and drowsiness
- Excitatory seizures in all exposed individuals
- Painful neuropathy within minutes of exposure
- Hypertensive crisis and tachycardia only
Correct Answer: Depressant effects, including dizziness and drowsiness
Q41. Which of the following describes tetrachloroethylene’s flammability classification?
- Generally nonflammable under normal conditions
- Highly flammable with low flash point
- Spontaneously combusts in air
- Explosive when mixed with water
Correct Answer: Generally nonflammable under normal conditions
Q42. Which property of tetrachloroethylene contributes to worker exposure risk in enclosed spaces?
- High vapor pressure relative to its boiling point, producing significant vapors
- Instant polymerization preventing vapor formation
- Strong odor even at very low concentrations deterring use
- Complete lack of volatility making inhalation impossible
Correct Answer: High vapor pressure relative to its boiling point, producing significant vapors
Q43. Which biological monitoring marker can indicate exposure to tetrachloroethylene?
- Presence of parent solvent or metabolites in exhaled breath or urine
- Elevated serum cholesterol exclusively
- Increased red blood cell count
- Positive glucose on urine dipstick
Correct Answer: Presence of parent solvent or metabolites in exhaled breath or urine
Q44. Which chemical reaction is least likely with tetrachloroethylene under mild conditions?
- Acid-catalyzed hydration to yield an alcohol
- Vapor-phase recovery by distillation
- Physical dissolution of nonpolar organics
- Photolytic degradation under specialized conditions
Correct Answer: Acid-catalyzed hydration to yield an alcohol
Q45. When selecting an absorbent for a spill of tetrachloroethylene, which property is most desirable?
- Hydrophobic sorbents that uptake chlorinated organic liquids
- Water-based sorbents that trap only aqueous spills
- Sorbents that rapidly neutralize acids only
- Biological compost that accelerates oxidation immediately
Correct Answer: Hydrophobic sorbents that uptake chlorinated organic liquids
Q46. Which is a common industrial substitute considered for tetrachloroethylene to reduce health risks?
- Less hazardous non-chlorinated solvents or advanced wet-cleaning technologies
- Increased use of carbon tetrachloride
- Widespread adoption of trichloroethylene without controls
- Mixing with leaded gas for increased solvency
Correct Answer: Less hazardous non-chlorinated solvents or advanced wet-cleaning technologies
Q47. Which analytical parameter helps distinguish tetrachloroethylene from similar chlorinated solvents in GC-MS?
- Characteristic retention time and mass spectral fragmentation pattern
- Its pH in aqueous solution
- Color change on simple litmus paper
- Electrical conductivity in dilute solution
Correct Answer: Characteristic retention time and mass spectral fragmentation pattern
Q48. In the context of drug product manufacturing, why must tetrachloroethylene contamination be controlled strictly?
- Potential toxic and carcinogenic residues compromise product safety
- It enhances the efficacy of pharmaceuticals undesirably
- It is an approved excipient for all drug dosage forms
- It stabilizes proteins and increases shelf life uncontrollably
Correct Answer: Potential toxic and carcinogenic residues compromise product safety
Q49. Which emergency action is appropriate for a person with suspected inhalation exposure to tetrachloroethylene?
- Move the person to fresh air and seek medical evaluation for CNS effects
- Have the person drink large amounts of water immediately
- Apply ice packs to the abdomen only
- Encourage vigorous exercise to metabolize the solvent faster
Correct Answer: Move the person to fresh air and seek medical evaluation for CNS effects
Q50. Which statement best summarizes why B. Pharm students should study the structure and uses of tetrachloroethylene?
- Understanding its structure informs reactivity, pharmaceutically relevant uses, toxicology and safe handling
- It is a first-line therapeutic agent in many formulations
- It replaces water in most pharmaceutical processes
- It is a nutrient required for tablet formation
Correct Answer: Understanding its structure informs reactivity, pharmaceutically relevant uses, toxicology and safe handling
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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