Structure and uses of chloral hydrate MCQs With Answer

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Introduction: Chloral hydrate is a classical sedative-hypnotic studied in pharmaceutical chemistry and pharmacology. This concise guide for B. Pharm students focuses on the structure and uses of chloral hydrate MCQs With Answer, covering chemical structure (CCl3CH(OH)2), IUPAC name, physicochemical properties, metabolism to trichloroethanol, mechanism at GABA-A receptors, formulations, dosing considerations, adverse effects, interactions and analytical methods. Emphasis is placed on synthesis, stability, quality control and safety to prepare you for examinations and practical pharmaceutical work. The questions that follow are designed to deepen conceptual understanding and application in drug development, therapeutics and forensic analysis. Now let’s test your knowledge with 50 MCQs on this topic.

Q1. What is the molecular formula of chloral hydrate?

  • C2H3Cl3O2
  • C2H4Cl2O2
  • C2H3ClO2
  • C3H3Cl3O

Correct Answer: C2H3Cl3O2

Q2. Which IUPAC name corresponds to chloral hydrate?

  • Trichloroethanol
  • 2,2,2-trichloro-1,1-ethanediol
  • Trichloroacetic acid
  • 1,1,1-trichloroethane

Correct Answer: 2,2,2-trichloro-1,1-ethanediol

Q3. Which functional groups are present in chloral hydrate?

  • Primary alcohol and ester
  • Geminal diol and trichloromethyl group
  • Aldehyde and ether
  • Carboxylic acid and halide

Correct Answer: Geminal diol and trichloromethyl group

Q4. What is the physical state of pure chloral hydrate at room temperature?

  • Colorless crystalline solid
  • Colorless gas
  • Oily liquid
  • Colored powder

Correct Answer: Colorless crystalline solid

Q5. Approximately what is the melting point of chloral hydrate?

  • 57–58 °C
  • 0–5 °C
  • 120–125 °C
  • –10 to –5 °C

Correct Answer: 57–58 °C

Q6. Chloral hydrate is best described as:

  • Insoluble in water
  • Highly soluble in water
  • Only soluble in nonpolar solvents
  • Hydrophobic crystalline salt

Correct Answer: Highly soluble in water

Q7. Chloral hydrate is formed by hydration of which compound?

  • Trichloroacetic acid
  • Chloral (trichloroacetaldehyde)
  • Trichloroethanol
  • Chloroform

Correct Answer: Chloral (trichloroacetaldehyde)

Q8. What is the primary active metabolite responsible for chloral hydrate’s sedative effects?

  • Trichloroacetic acid
  • Trichloroethanol
  • Chloroform
  • Chloral

Correct Answer: Trichloroethanol

Q9. Which enzyme predominantly reduces chloral to trichloroethanol?

  • Monoamine oxidase
  • Alcohol dehydrogenase
  • CYP3A4
  • Acetylcholinesterase

Correct Answer: Alcohol dehydrogenase

Q10. The sedative action of chloral hydrate is mainly due to modulation of which receptor system?

  • Dopamine D2 receptors
  • GABA-A receptor complex
  • Nicotinic acetylcholine receptors
  • Opioid receptors

Correct Answer: GABA-A receptor complex

Q11. Which metabolite is associated with prolonged toxicity and accumulation after repeated chloral hydrate use?

  • Chloral
  • Trichloroacetic acid
  • Trichloroethanol glucuronide
  • Chloroethane

Correct Answer: Trichloroacetic acid

Q12. Typical onset of oral chloral hydrate sedative effect is usually within:

  • 15–60 minutes
  • 4–6 hours
  • Immediately (<1 minute)
  • 24 hours

Correct Answer: 15–60 minutes

Q13. The elimination half-life of the active metabolite trichloroethanol is approximately:

  • 8–12 hours
  • 30 minutes
  • 48–72 hours
  • 1–2 hours

Correct Answer: 8–12 hours

Q14. Historically, chloral hydrate has been used clinically as a:

  • Antibiotic
  • Sedative-hypnotic and preanesthetic sedative
  • Anticonvulsant of first-line use
  • Topical antiseptic

Correct Answer: Sedative-hypnotic and preanesthetic sedative

Q15. Concomitant use of chloral hydrate with which substance is particularly hazardous?

  • Nonsteroidal anti-inflammatory drugs
  • Ethanol (alcohol)
  • Vitamin C supplements
  • Topical emollients

Correct Answer: Ethanol (alcohol)

Q16. The most serious acute adverse effect of chloral hydrate overdose is:

  • Severe gastrointestinal bleeding
  • Central respiratory depression leading to respiratory failure
  • Renal stone formation
  • Acute pancreatitis

Correct Answer: Central respiratory depression leading to respiratory failure

Q17. Common impurities or related substances monitored during quality control include:

  • Trichloroethanol and trichloroacetic acid
  • Chloroform and chlorobenzene
  • Acetone and methanol
  • Benzene and toluene

Correct Answer: Trichloroethanol and trichloroacetic acid

Q18. Which analytical technique is most suitable for sensitive identification of chloral hydrate and volatile metabolites in biological samples?

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

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

Q19. Does chloral hydrate possess stereocenters and chirality?

  • Yes, it is chiral with one stereocenter
  • No, it is achiral (no stereocenters)
  • Yes, it has two stereocenters
  • Chirality depends on pH

Correct Answer: No, it is achiral (no stereocenters)

Q20. Which statement best describes thermal behavior of chloral hydrate?

  • Highly volatile with a normal boiling point at 80 °C
  • Stable to very high temperatures without decomposition
  • Crystalline and decomposes on strong heating rather than having a simple boiling point
  • Explosive when heated

Correct Answer: Crystalline and decomposes on strong heating rather than having a simple boiling point

Q21. Chloral hydrate stability is affected by pH. It is most likely to decompose under:

  • Strongly acidic conditions
  • Neutral buffered conditions only
  • Alkaline conditions
  • Pure oxygen atmosphere only

Correct Answer: Alkaline conditions

Q22. Chloral hydrate is best characterized in terms of therapeutic index as:

  • Wide therapeutic index
  • Narrow therapeutic index
  • No therapeutic index (nonpharmacologic)
  • Variable depending on solvent

Correct Answer: Narrow therapeutic index

Q23. Which population is particularly vulnerable to exaggerated effects of chloral hydrate?

  • Young adults aged 20–30 exclusively
  • Elderly patients and those with hepatic impairment
  • Healthy athletes
  • Patients with hyperthyroidism only

Correct Answer: Elderly patients and those with hepatic impairment

Q24. Prolonged or repeated exposure to chloral hydrate may lead to which organ toxicity?

  • Hepatic toxicity
  • Bone marrow aplasia exclusively
  • Osteoporosis
  • Acute myocardial infarction

Correct Answer: Hepatic toxicity

Q25. Common pharmaceutical formulations historically available for chloral hydrate included:

  • Topical ointments only
  • Oral solutions/syrups and tablets
  • Injectable emulsions for IV use routinely
  • Nasal sprays

Correct Answer: Oral solutions/syrups and tablets

Q26. A standard laboratory synthesis route for chloral hydrate involves which key steps?

  • Nitration of ethanol followed by reduction
  • Chlorination of acetaldehyde to chloral followed by hydration
  • Hydrogenation of chloroform
  • Oxidation of trichloroethanol only

Correct Answer: Chlorination of acetaldehyde to chloral followed by hydration

Q27. Regulatory status of chloral hydrate in many countries is best described as:

  • Over-the-counter antihistamine
  • Restricted/regulated due to safety concerns
  • Completely unrestricted dietary supplement
  • First-line treatment for insomnia in guidelines

Correct Answer: Restricted/regulated due to safety concerns

Q28. The primary mechanism of acute fatality in chloral hydrate overdose is through:

  • Severe electrolyte imbalance alone
  • Progressive CNS and respiratory depression from trichloroethanol
  • Severe allergic reaction only
  • Renal failure in the first hour

Correct Answer: Progressive CNS and respiratory depression from trichloroethanol

Q29. In IR spectroscopy of chloral hydrate, one would expect a strong broad absorption due to:

  • C–H stretching only
  • O–H stretching (broad) and C–Cl characteristic bands
  • N–H stretching
  • Sulfhydryl stretching

Correct Answer: O–H stretching (broad) and C–Cl characteristic bands

Q30. Chloral hydrate is pharmacologically classified primarily as a:

  • Stimulant
  • CNS depressant (sedative-hypnotic)
  • Local anesthetic
  • Antidepressant

Correct Answer: CNS depressant (sedative-hypnotic)

Q31. Which co-administered drug class would most likely potentiate chloral hydrate’s sedative effects?

  • Beta-blockers
  • Benzodiazepines and opioids
  • Proton pump inhibitors
  • Topical corticosteroids

Correct Answer: Benzodiazepines and opioids

Q32. Which statement is correct regarding chloral hydrate and alcohol intoxication signs?

  • Chloral hydrate produces stimulant-like signs opposite to alcohol
  • Effects are similar to ethanol and can be additive
  • Chloral hydrate blocks alcohol metabolism entirely
  • Chloral hydrate neutralizes alcohol toxicity

Correct Answer: Effects are similar to ethanol and can be additive

Q33. In modern practice, chloral hydrate is most likely to be used:

  • As the first-line hypnotic in adults
  • Rarely, sometimes for short-term pediatric sedation or niche uses
  • As a routine antibiotic adjunct
  • As a topical antifungal

Correct Answer: Rarely, sometimes for short-term pediatric sedation or niche uses

Q34. Appropriate storage conditions for chloral hydrate include:

  • Open container at room temperature exposed to light
  • Cool, dry, dark, tightly closed container
  • Freezer at −80 °C only
  • Mixed with acids to stabilize

Correct Answer: Cool, dry, dark, tightly closed container

Q35. A reliable assay method for pharmaceutical quality control of chloral hydrate in formulations is:

  • High-performance liquid chromatography (HPLC)
  • Simple pH paper test
  • Microscopic particle counting only
  • Chiral column gas chromatography for enantiomers

Correct Answer: High-performance liquid chromatography (HPLC)

Q36. Chloral hydrate’s boiling behavior is best described as:

  • Normal boiling point at 100 °C
  • Decomposes on heating and does not have a simple normal boiling point
  • Boils at −20 °C under atmospheric pressure
  • Sub-limes directly from solid to gas at room temperature

Correct Answer: Decomposes on heating and does not have a simple normal boiling point

Q37. The primary receptor subtype thought to mediate trichloroethanol’s action is located on which neurotransmitter system?

  • Serotonergic 5-HT3
  • GABAergic (GABA-A)
  • Adrenergic alpha-2
  • Histaminergic H1

Correct Answer: GABAergic (GABA-A)

Q38. Phase II metabolism of trichloroethanol commonly involves which conjugation?

  • Glucuronidation
  • Methylation only
  • Sulfation exclusively
  • Acetylation

Correct Answer: Glucuronidation

Q39. Chronic abuse or long-term exposure to chloral hydrate may lead to accumulation of which metabolite causing toxicity?

  • Ethyl alcohol
  • Trichloroacetic acid leading to potential hepatotoxicity
  • Increased glucose formation
  • Benzoic acid accumulation

Correct Answer: Trichloroacetic acid leading to potential hepatotoxicity

Q40. Reduction of chloral hydrate yields which compound?

  • Chloroform
  • Trichloroethanol
  • Acetone
  • Trichloroacetic acid

Correct Answer: Trichloroethanol

Q41. Does chloral hydrate have significant intrinsic analgesic properties?

  • Yes, it is a potent analgesic
  • No, it is primarily a sedative-hypnotic with negligible analgesic effect
  • It is solely an anti-inflammatory agent
  • It acts as a local anesthetic

Correct Answer: No, it is primarily a sedative-hypnotic with negligible analgesic effect

Q42. Which statement about chloral hydrate’s role in modern formularies is most accurate?

  • Widely recommended as first-line insomnia therapy
  • Rarely used; largely replaced by safer hypnotics
  • Commonly used as an over-the-counter sleep aid
  • Standard therapy for chronic anxiety

Correct Answer: Rarely used; largely replaced by safer hypnotics

Q43. Primary emergency management of severe chloral hydrate overdose focuses on:

  • Immediate hemodialysis as first-line in all cases
  • Supportive care: airway protection, ventilation and circulatory support
  • Administration of high-dose aspirin
  • Neutralization with alkaline solutions orally

Correct Answer: Supportive care: airway protection, ventilation and circulatory support

Q44. Which age group shows increased sensitivity and risk of prolonged sedation with chloral hydrate?

  • Adolescents exclusively
  • Infants and the elderly
  • Middle-aged healthy adults only
  • Professional athletes

Correct Answer: Infants and the elderly

Q45. Chloral hydrate can be considered a prodrug because:

  • It is inactive and is converted enzymatically to trichloroethanol which mediates effects
  • It is active only as the free base in tissues
  • It is immediately active without metabolism
  • It generates an active insulin analog biologically

Correct Answer: It is inactive and is converted enzymatically to trichloroethanol which mediates effects

Q46. Chronic exposure to chloral hydrate is most likely to alter which laboratory parameter?

  • Fasting blood glucose only
  • Elevated liver enzymes (ALT/AST) with hepatotoxicity
  • Platelet count increases markedly
  • Urinary glucose always positive

Correct Answer: Elevated liver enzymes (ALT/AST) with hepatotoxicity

Q47. Which forensic clue might suggest administration of chloral hydrate in a clinical or toxicological sample?

  • Detection of trichloroethanol and trichloroacetic acid metabolites
  • High benzoylecgonine levels
  • Elevated acetaminophen only
  • Presence of amphetamine metabolites

Correct Answer: Detection of trichloroethanol and trichloroacetic acid metabolites

Q48. During formulation development, an important compatibility concern for chloral hydrate includes reaction with:

  • Strong reducing agents and alkalis causing decomposition
  • Neutral excipients only
  • Distilled water exclusively
  • Inert polymers with no reaction

Correct Answer: Strong reducing agents and alkalis causing decomposition

Q49. For detection and quantification of chloral hydrate in pharmaceutical preparations, which chromatographic detector enhances selectivity for halogenated species?

  • Refractive index detector
  • Electron capture detector (ECD) often coupled with GC
  • Simple UV detector at 220 nm only
  • Nitrogen-phosphorus detector (NPD)

Correct Answer: Electron capture detector (ECD) often coupled with GC

Q50. Which precaution is most appropriate when teaching B. Pharm students about chloral hydrate handling in the lab?

  • No special precautions; handle as nonhazardous
  • Use gloves, goggles, and avoid ingestion or skin contact; dispose of waste per regulations
  • Only store at room temperature in open flasks
  • Mix freely with strong alkalis to neutralize

Correct Answer: Use gloves, goggles, and avoid ingestion or skin contact; dispose of waste per regulations

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