Structure and uses of methyl alcohol MCQs With Answer

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Structure and uses of methyl alcohol MCQs With Answer – This concise introduction explains methanol (methyl alcohol) for B.Pharm students, covering chemical structure (CH3OH), bonding, polarity, hydrogen bonding, physical properties, production (syngas hydrogenation), and pharmaceutical-relevant uses such as solvents, reagents for methylation and esterification, and as an industrial precursor to formaldehyde and acetic acid. It also touches toxicology, metabolic pathways (alcohol dehydrogenase → formaldehyde → formic acid), clinical management (ethanol, fomepizole, dialysis), safety, analysis (GC, IR) and handling. These keyword-rich points prepare you for detailed learning and assessments. Now let’s test your knowledge with 50 MCQs on this topic.

Q1. What is the molecular formula of methyl alcohol (methanol)?

  • CH4
  • CH3OH
  • C2H5OH
  • CH3OCH3

Correct Answer: CH3OH

Q2. Which phrase best describes the structure of methyl alcohol?

  • Two methyl groups bonded together
  • One methyl group bonded to a hydroxyl (-OH) group
  • A benzene ring with an -OH group
  • A methylene group between two oxygens

Correct Answer: One methyl group bonded to a hydroxyl (-OH) group

Q3. What is the hybridization state of the carbon atom in methanol?

  • sp
  • sp2
  • sp3
  • sp3d

Correct Answer: sp3

Q4. Approximately what is the C–O–H bond angle environment around the carbon in methanol?

  • 120°
  • 180°
  • 109.5°
  • 90°

Correct Answer: 109.5°

Q5. Why is methanol considered a polar molecule?

  • Only because it contains carbon
  • Because of the polar O–H and C–O bonds and its dipole moment
  • Because it is a gas at room temperature
  • Because it has no dipole

Correct Answer: Because of the polar O–H and C–O bonds and its dipole moment

Q6. Can methanol form hydrogen bonds?

  • No, it cannot
  • Yes, it can form hydrogen bonds with itself and water
  • Only with nonpolar solvents
  • Only at very low temperatures

Correct Answer: Yes, it can form hydrogen bonds with itself and water

Q7. What is the solubility of methanol in water?

  • Insoluble
  • Partially soluble (about 10%)
  • Miscible with water
  • Soluble only in organic solvents

Correct Answer: Miscible with water

Q8. What is the approximate pKa of methanol?

  • ~4
  • ~8
  • ~16
  • ~25

Correct Answer: ~16

Q9. What is the approximate boiling point of methanol at 1 atm?

  • 0 °C
  • 64.7 °C
  • 100 °C
  • 153 °C

Correct Answer: 64.7 °C

Q10. Which industrial process is primarily used to produce methanol on a large scale?

  • Fermentation of sugars
  • Catalytic hydrogenation of carbon monoxide (synthesis gas)
  • Direct electrolysis of water
  • Steam distillation of crude oil

Correct Answer: Catalytic hydrogenation of carbon monoxide (synthesis gas)

Q11. Which catalyst system is commonly used for industrial methanol synthesis from syngas?

  • Platinum on carbon
  • Cu/ZnO/Al2O3
  • Fe2O3
  • Pd/C

Correct Answer: Cu/ZnO/Al2O3

Q12. What major industrial chemical is produced from methanol by catalytic oxidation?

  • Acetone
  • Formaldehyde
  • Ethylene
  • Acetonitrile

Correct Answer: Formaldehyde

Q13. Which enzyme principally metabolizes methanol in humans?

  • Catalase
  • Alcohol dehydrogenase (ADH)
  • Aldolase
  • Monoamine oxidase

Correct Answer: Alcohol dehydrogenase (ADH)

Q14. What are the toxic metabolites produced from methanol metabolism?

  • Acetaldehyde and acetic acid
  • Formaldehyde and formic acid (formate)
  • Benzaldehyde and benzoic acid
  • Propionaldehyde and propionic acid

Correct Answer: Formaldehyde and formic acid (formate)

Q15. What characteristic clinical feature is classically associated with severe methanol poisoning?

  • Hearing loss
  • Visual disturbances or blindness
  • Skin rash
  • Hypertension only

Correct Answer: Visual disturbances or blindness

Q16. Which treatments are first-line antidotes for methanol poisoning?

  • Naloxone or flumazenil
  • Vitamin C and thiamine
  • Ethanol or fomepizole (4-methylpyrazole)
  • Atropine and pralidoxime

Correct Answer: Ethanol or fomepizole (4-methylpyrazole)

Q17. What is the primary mechanism leading to metabolic acidosis in methanol toxicity?

  • Accumulation of lactic acid from anaerobic metabolism
  • Accumulation of formic acid (formate) from methanol metabolism
  • Excessive production of carbon dioxide
  • Renal loss of bicarbonate due to methanol diuresis

Correct Answer: Accumulation of formic acid (formate) from methanol metabolism

Q18. Which of the following is a common pharmaceutical use of methanol?

  • Active pharmaceutical ingredient in tablets
  • Nonpolar solvent for hydrophobic drugs
  • Polar organic solvent and extraction medium in synthesis and purification
  • Parenteral diluent for injectables

Correct Answer: Polar organic solvent and extraction medium in synthesis and purification

Q19. In organic synthesis, methanol is commonly used to form which functional group by Fischer-type reactions?

  • Amides
  • Methyl esters (via esterification/transesterification)
  • Thioethers
  • Alkenes

Correct Answer: Methyl esters (via esterification/transesterification)

Q20. What is “denatured alcohol” in which methanol is often used?

  • Sterile surgical alcohol
  • Ethanol with additives such as methanol to render it unfit for drinking
  • Methanol purified for pharmaceutical use
  • Ethylene glycol mixed with dyes

Correct Answer: Ethanol with additives such as methanol to render it unfit for drinking

Q21. What is the approximate flash point of methanol (closed cup)?

  • −20 °C
  • 11 °C
  • 100 °C
  • 250 °C

Correct Answer: 11 °C

Q22. What is the approximate autoignition temperature of methanol?

  • 180 °C
  • 260 °C
  • 464 °C
  • 900 °C

Correct Answer: 464 °C

Q23. Which of the following best describes the density (specific gravity) of methanol at 20 °C?

  • About 0.79 g/mL (less dense than water)
  • About 1.2 g/mL (denser than water)
  • Equal to water (1.0 g/mL)
  • Less than air

Correct Answer: About 0.79 g/mL (less dense than water)

Q24. Which statement about methanol’s behavior in the environment is correct?

  • Highly persistent and bioaccumulative
  • Non-biodegradable
  • Readily biodegradable and low bioaccumulation potential
  • Forms permanent soil complexes

Correct Answer: Readily biodegradable and low bioaccumulation potential

Q25. In clinical testing, what laboratory finding is indicative of severe methanol poisoning?

  • Metabolic alkalosis with low chloride
  • High anion gap metabolic acidosis with elevated serum formate
  • Isolated hyperkalemia only
  • Low serum lactate with normal pH

Correct Answer: High anion gap metabolic acidosis with elevated serum formate

Q26. Which IR absorption band is characteristic for the O–H stretch in methanol?

  • ~1700 cm−1
  • ~2100 cm−1
  • ~3200–3600 cm−1
  • ~600 cm−1

Correct Answer: ~3200–3600 cm−1

Q27. In 1H NMR spectroscopy, where does the methyl (CH3) proton signal of methanol typically appear?

  • ~0.9 ppm
  • ~1.2 ppm
  • ~3.3–3.5 ppm
  • ~7.2 ppm

Correct Answer: ~3.3–3.5 ppm

Q28. What is the molecular ion peak (approximate m/z) for methanol in mass spectrometry (M+)?

  • m/z 18
  • m/z 32
  • m/z 44
  • m/z 28

Correct Answer: m/z 32

Q29. What is the product when methanol reacts with sodium metal?

  • Dimethyl ether and hydrogen
  • Sodium methoxide and hydrogen gas
  • Methane and sodium hydroxide
  • Sodium methyl sulfate

Correct Answer: Sodium methoxide and hydrogen gas

Q30. The primary oxidation product of methanol (one-step oxidation) is:

  • Acetic acid
  • Formaldehyde
  • Acetaldehyde
  • Carbon dioxide directly

Correct Answer: Formaldehyde

Q31. Which of the following consumer applications commonly contains methanol?

  • Soft drinks
  • Windshield washer fluids and some antifreeze/de-icing products
  • Sterile saline for injection
  • Bread and bakery products

Correct Answer: Windshield washer fluids and some antifreeze/de-icing products

Q32. How is methanol used in the context of fuels?

  • Not used at all in fuels
  • Used as a fuel or fuel additive and in methanol fuel cells
  • Used exclusively in diesel engines without modification
  • Only used as a solid rocket propellant

Correct Answer: Used as a fuel or fuel additive and in methanol fuel cells

Q33. In biodiesel production, what role does methanol play?

  • Catalyst that speeds up polymerization
  • Solvent that dissolves glycerol only
  • Alcohol used in transesterification to form methyl esters (biodiesel)
  • Neutralizing agent

Correct Answer: Alcohol used in transesterification to form methyl esters (biodiesel)

Q34. Which personal protective equipment (PPE) is essential when handling methanol in the lab?

  • Light clothing only
  • Gloves, splash goggles, lab coat and adequate ventilation (fume hood)
  • No PPE is required
  • Only a respirator, no eye protection

Correct Answer: Gloves, splash goggles, lab coat and adequate ventilation (fume hood)

Q35. Best practice for storing methanol in a laboratory is to:

  • Store near strong oxidizers for convenience
  • Keep in a tightly closed container away from heat and ignition sources
  • Store at high temperature to prevent freezing
  • Store in clear glass on open bench

Correct Answer: Keep in a tightly closed container away from heat and ignition sources

Q36. Which analytical technique is commonly used for quantification of methanol in biological samples?

  • Thin-layer chromatography (TLC)
  • Gas chromatography (GC) often with FID or MS detection
  • UV-Vis spectrophotometry at 260 nm
  • Paper chromatography

Correct Answer: Gas chromatography (GC) often with FID or MS detection

Q37. Methanol is classified chemically as which type of alcohol?

  • Secondary alcohol
  • Tertiary alcohol
  • Primary alcohol
  • Phenol

Correct Answer: Primary alcohol

Q38. Is methanol a chiral molecule?

  • Yes, it is chiral
  • No, it is achiral
  • Only when bound to metals
  • Only at high temperature

Correct Answer: No, it is achiral

Q39. Which ion formed from methanol metabolism is directly implicated in optic nerve toxicity?

  • Acetate ion
  • Formate ion
  • Propionate ion
  • Nitrate ion

Correct Answer: Formate ion

Q40. Which of the following industrial products is commonly manufactured using formaldehyde derived from methanol?

  • Polyethylene
  • Phenol-formaldehyde resins (e.g., Bakelite) and other resins
  • Natural rubber
  • Polypropylene

Correct Answer: Phenol-formaldehyde resins (e.g., Bakelite) and other resins

Q41. For severe methanol poisoning with high formate levels and visual symptoms, which therapy is indicated to rapidly remove methanol and formate?

  • Activated charcoal only
  • Hemodialysis
  • Oral rehydration only
  • Topical ointment application

Correct Answer: Hemodialysis

Q42. Which statement about methanol’s miscibility with organic solvents is correct?

  • Methanol is immiscible with most organic solvents
  • Methanol is miscible with many polar and some less-polar organic solvents
  • Methanol only mixes with hydrocarbons
  • Methanol dissolves ionic solids but not organic compounds

Correct Answer: Methanol is miscible with many polar and some less-polar organic solvents

Q43. Which reagent commonly used in organic chemistry is formed by deprotonation of methanol?

  • Sodium hydroxide
  • Sodium methoxide (CH3ONa)
  • Potassium permanganate
  • Hydrochloric acid

Correct Answer: Sodium methoxide (CH3ONa)

Q44. Which test would best separate and quantify methanol in a mixed-alcohol sample in a pharmaceutical QC lab?

  • Gravimetric analysis
  • Gas chromatography with an appropriate column
  • Paper spot test
  • Simple boiling point observation without instrumentation

Correct Answer: Gas chromatography with an appropriate column

Q45. Which transport hazard class does methanol fall under for regulatory shipping?

  • Class 1: Explosives
  • Class 3: Flammable liquids
  • Class 6.1: Toxic substances only
  • Class 8: Corrosives only

Correct Answer: Class 3: Flammable liquids

Q46. Does methanol cause effects on the central nervous system similar to ethanol?

  • No, methanol has no CNS effects
  • Yes, it causes CNS depression but also has unique toxic metabolites
  • It causes stimulation, not depression
  • It only affects peripheral nerves, not CNS

Correct Answer: Yes, it causes CNS depression but also has unique toxic metabolites

Q47. Which measure can be used to prevent formation of toxic metabolites when treating suspected methanol ingestion?

  • Administering fomepizole or ethanol to inhibit alcohol dehydrogenase
  • Giving high-dose antibiotics
  • Applying topical antidotes
  • Forced emesis only

Correct Answer: Administering fomepizole or ethanol to inhibit alcohol dehydrogenase

Q48. Which analytical marker is most directly measured to assess methanol exposure resulting in toxicity?

  • Serum chloride
  • Serum formate (formic acid) concentration and anion gap
  • Blood urea nitrogen only
  • Serum albumin level

Correct Answer: Serum formate (formic acid) concentration and anion gap

Q49. Which common organic reaction uses methanol as a reactant to produce methyl derivatives useful in pharmaceutical synthesis?

  • Nitration to produce nitromethane
  • Transesterification to produce methyl esters
  • Halogenation to produce chloromethane directly at room temperature
  • Free radical polymerization to produce polyethylene

Correct Answer: Transesterification to produce methyl esters

Q50. What is the correct procedure for disposing small quantities of methanol waste in a pharmaceutical laboratory?

  • Pour down the sink with plenty of water
  • Evaporate in the hood and leave residues on the bench
  • Collect and dispose as hazardous chemical waste according to institutional and regulatory procedures
  • Incinerate openly in the lab without controls

Correct Answer: Collect and dispose as hazardous chemical waste according to institutional and regulatory procedures

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