Organic solvent hazards MCQs With Answer

Organic solvent hazards MCQs With Answer

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Organic solvent hazards MCQs With Answer

Introduction: Organic solvents are integral to pharmaceutical research and manufacturing but pose significant health, fire and environmental risks. This quiz set is designed for M.Pharm students to deepen understanding of solvent properties, exposure pathways, regulatory limits and practical safety controls. Questions cover toxicology (neurotoxicity, carcinogenicity, dermal absorption), physical properties (flash point, vapor pressure, LEL/UEL, autoignition), hazard communication (GHS, NFPA), engineering controls, personal protective equipment, emergency response and waste disposal. Working through these MCQs will help you apply hazard assessment principles, choose safer alternatives, and implement appropriate control strategies in laboratory and production settings.

Q1. Which term describes the lowest temperature at which a liquid produces enough vapour to form an ignitable mixture with air near the surface of the liquid?

  • Boiling point
  • Flash point
  • Autoignition temperature
  • Upper explosive limit (UEL)

Correct Answer: Flash point

Q2. In the NFPA 704 diamond, which color block represents the degree of health hazard posed by a chemical?

  • Red
  • Blue
  • Yellow
  • White

Correct Answer: Blue

Q3. Which solvent is known for exceptionally high dermal permeability and is often used as a vehicle to enhance transdermal delivery (therefore posing a notable skin absorption hazard)?

  • Toluene
  • Dimethyl sulfoxide (DMSO)
  • Hexane
  • Ethyl acetate

Correct Answer: Dimethyl sulfoxide (DMSO)

Q4. The Lower Explosive Limit (LEL) of a solvent vapor is best described as:

  • The maximum concentration of vapor in air that supports combustion
  • The minimum concentration of vapor in air that can propagate a flame
  • The concentration at which vapors become odorous
  • The concentration equivalent to the occupational exposure limit

Correct Answer: The minimum concentration of vapor in air that can propagate a flame

Q5. Which of the following common organic solvents is classified as a human carcinogen with well-documented association to hematologic malignancies?

  • Acetone
  • Benzene
  • Isopropanol
  • Ethyl acetate

Correct Answer: Benzene

Q6. The OSHA Permissible Exposure Limit (PEL) for an airborne solvent is typically expressed as which of the following?

  • Short-term exposure limit (15-minute ceiling)
  • 8-hour time-weighted average (TWA)
  • Instantaneous peak concentration
  • Biological exposure index (urinary metabolite)

Correct Answer: 8-hour time-weighted average (TWA)

Q7. For laboratory operations where solvent concentrations may exceed Immediately Dangerous to Life or Health (IDLH) values, which respiratory protection is required?

  • N95 particulate respirator
  • Half-mask organic vapor cartridge respirator
  • Supplied-air respirator (SAR)
  • Self-contained breathing apparatus (SCBA)

Correct Answer: Self-contained breathing apparatus (SCBA)

Q8. According to the hierarchy of controls, which option is the most effective approach to manage organic solvent hazards?

  • Personal protective equipment
  • Administrative controls (training, procedures)
  • Engineering controls (local exhaust ventilation)
  • Elimination or substitution of the hazardous solvent

Correct Answer: Elimination or substitution of the hazardous solvent

Q9. Which physical property most directly correlates with a solvent’s volatility at a given temperature?

  • Viscosity
  • Vapor pressure
  • Surface tension
  • Dielectric constant

Correct Answer: Vapor pressure

Q10. Chronic occupational exposure to which solvent is classically associated with peripheral neuropathy due to axonal degeneration?

  • Methanol
  • Toluene
  • n-Hexane
  • Chloroform

Correct Answer: n-Hexane

Q11. Which of the following pairs represents an unsafe storage combination because strong oxidizers can react violently with organic solvents?

  • Sodium chloride and water
  • Sulfuric acid and sodium hydroxide
  • Acetone and nitric acid
  • Hexane and glass containers

Correct Answer: Acetone and nitric acid

Q12. On discovery of a small laboratory spill of a flammable solvent, which immediate action is most appropriate to reduce risk?

  • Evacuate the building without attempting containment
  • Ignite a pilot flame to consume vapors
  • Eliminate ignition sources and ventilate the area, then absorb spill with inert material
  • Wash the spill into the sink with large volumes of water

Correct Answer: Eliminate ignition sources and ventilate the area, then absorb spill with inert material

Q13. Which GHS pictogram specifically communicates the hazard “flammable liquid” on a chemical label?

  • Health hazard pictogram (silhouette with star)
  • Exclamation mark pictogram
  • Environment pictogram (dead tree/fish)
  • Flame pictogram

Correct Answer: Flame pictogram

Q14. The boiling point of a solvent is best defined as:

  • The temperature at which the vapor pressure equals ambient atmospheric pressure
  • The temperature at which the liquid first emits an ignitable vapor
  • The lowest temperature at which a solvent autooxidizes
  • The temperature at which viscosity becomes zero

Correct Answer: The temperature at which the vapor pressure equals ambient atmospheric pressure

Q15. Biological monitoring of solvent exposure commonly measures which of the following to assess internal dose?

  • Real-time personal air sample concentrations
  • Colorimetric gas detector tube readings
  • Urinary metabolites specific to the solvent
  • Odor threshold detection by workers

Correct Answer: Urinary metabolites specific to the solvent

Q16. Which solvent is most suitable for extracting nonpolar lipids from a biological sample due to its nonpolar nature?

  • Water
  • Acetone
  • n-Hexane
  • Methanol

Correct Answer: n-Hexane

Q17. Autoignition temperature of a solvent is defined as:

  • The temperature at which a solvent forms a combustible vapor-air mixture
  • The temperature at which the solvent will spontaneously ignite without an external ignition source
  • The temperature at which solvent decomposes to toxic products
  • The temperature at which solvent freezes

Correct Answer: The temperature at which the solvent will spontaneously ignite without an external ignition source

Q18. Which statement correctly compares flash point and fire point of a solvent?

  • Flash point is higher than fire point
  • Flash point and fire point are identical
  • Flash point is lower than fire point
  • Flash point measures toxicity while fire point measures flammability

Correct Answer: Flash point is lower than fire point

Q19. Which ventilation strategy is most effective at controlling solvent exposure at the source?

  • General dilution (room) ventilation only
  • Local exhaust ventilation (capture at source)
  • Opening windows to increase cross-ventilation
  • Relying solely on personal protective equipment

Correct Answer: Local exhaust ventilation (capture at source)

Q20. For disposal of bulk quantities of spent organic solvents from a pharmaceutical lab, the preferred approach is to:

  • Pour them down the laboratory sink with soapy water
  • Evaporate them in the fume hood
  • Collect and transfer to a labeled hazardous waste container for disposal by a licensed hazardous waste contractor
  • Burn them outdoors away from the facility

Correct Answer: Collect and transfer to a labeled hazardous waste container for disposal by a licensed hazardous waste contractor

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