Laboratory Safety Practice Questions
20 free Laboratory Safety practice questions for the General Science. Tap an option to answer — you get instant feedback, the correct answer, and a detailed explanation for every question.
Which of the following is the correct procedure when diluting a concentrated acid with water?
- A Pour the water quickly into the acid
- B Always add the acid to the water slowly
- C Mix them simultaneously in a beaker
- D Always add the water to the acid slowly
Correct answer: Always add the acid to the water slowly
Adding acid to water is safer because the large volume of water absorbs the heat that is released (remember: Always Add Acid). Adding water to concentrated acid can make the mixture flash-boil and splash corrosive liquid out of the container.
What does a 'Skull and Crossbones' symbol on a chemical container signify?
- A The substance is highly flammable and ignites easily
- B The substance is corrosive to metals
- C The substance is acutely toxic or poisonous
- D The substance is an environmental hazard
Correct answer: The substance is acutely toxic or poisonous
The skull and crossbones is a standard GHS hazard pictogram indicating that the chemical can cause death or toxicity even in small quantities. It alerts the user that ingestion, inhalation, or skin contact must be strictly avoided.
In the event of a chemical splash in the eyes, what is the minimum recommended time to rinse the eyes at an eyewash station?
- A 2 minutes
- B 5 minutes
- C 15 minutes
- D 60 minutes
Correct answer: 15 minutes
Safety protocols require flushing the eyes for at least 15 to 20 minutes to ensure all traces of the chemical are diluted and removed. This duration is necessary because chemicals can continue to damage ocular tissue even after the initial splash.
Which piece of laboratory equipment should always be used when handling volatile or foul-smelling chemicals?
- A Analytical balance
- B Fume hood
- C Centrifuge
- D Incubator
Correct answer: Fume hood
A fume hood provides localized ventilation to protect the user from inhaling hazardous vapors, gases, or dusts. It draws air away from the user and filters or exhausts it safely outside the building.
What is the primary purpose of wearing safety goggles in a chemistry lab, even if you wear prescription eyeglasses?
- A To improve visual clarity and magnification during experiments
- B To prevent the lenses from fogging up due to steam
- C To provide impact and splash protection from all sides
- D To protect the face from ultraviolet radiation
Correct answer: To provide impact and splash protection from all sides
Standard prescription glasses do not provide adequate protection against lateral splashes or fine mists. Safety goggles are designed to seal against the face or provide side shields to prevent hazardous materials from reaching the eyes.
A document that provides detailed information about a chemical's properties, hazards, and first-aid measures is called a:
- A Lab Notebook
- B Safety Data Sheet (SDS)
- C Standard Operating Procedure (SOP)
- D Chemical Inventory List
Correct answer: Safety Data Sheet (SDS)
An SDS contains 16 sections covering everything from toxicity to transport and disposal. It is a legal requirement for laboratories to provide access to an SDS for every hazardous chemical in use.
What is the correct way to smell a chemical substance in the laboratory if instructed to do so?
- A Place your nose directly over the container and inhale deeply
- B Pour a small amount on the table and sniff it
- C Heat the chemical first to increase the scent
- D Use your hand to waft the vapors toward your nose
Correct answer: Use your hand to waft the vapors toward your nose
Wafting (or fanning) the air above the container toward the nose prevents a concentrated dose of potentially toxic or irritating vapors from entering the lungs. Direct inhalation can cause immediate damage to the respiratory system.
Which type of fire extinguisher is generally best suited for fires involving flammable liquids or electrical equipment (Class B and C fires)?
- A Pressurized water extinguisher or hose
- B Compressed air canister
- C Carbon dioxide or dry chemical powder
- D Bucket of dry sand
Correct answer: Carbon dioxide or dry chemical powder
Water should never be used on grease or electrical fires as it can spread the flames or conduct electricity. CO2 extinguishers work by displacing oxygen and cooling the fuel without leaving a conductive residue.
When heating a test tube over a Bunsen burner, you should always point the open end of the tube:
- A Toward yourself to monitor the reaction
- B Toward the sink so any spillage is contained
- C Away from yourself and all other people
- D Downwards toward the base of the burner
Correct answer: Away from yourself and all other people
Liquids being heated can 'bump' or suddenly erupt from a test tube. Pointing the opening away from everyone ensures that if a sudden eruption occurs, no one will be sprayed with hot or corrosive chemicals.
Which of these is considered a 'Physical Hazard' rather than a chemical hazard in the lab?
- A Concentrated sulfuric acid solution
- B Mercury vapor
- C Ethyl alcohol vapor
- D High-pressure gas cylinders
Correct answer: High-pressure gas cylinders
While the gas inside might be chemically hazardous, the cylinder itself is a physical hazard due to the high pressure. If a valve is damaged, the cylinder can become a dangerous projectile.
If a small amount of a non-corrosive chemical is spilled on your lab coat, what should be your first action?
- A Immediately remove the lab coat and notify the instructor
- B Continue working until the end of the lab period and then wash it
- C Wash the lab coat while you are wearing it
- D Neutralize the spill with a strong base
Correct answer: Immediately remove the lab coat and notify the instructor
The primary purpose of a lab coat is to act as a sacrificial layer. Removing it immediately prevents the chemical from soaking through the fabric and coming into contact with your skin.
In the 'NFPA 704' diamond symbol, what does a '4' in the blue quadrant indicate?
- A Severe fire hazard
- B Chemically stable substance
- C Strong oxidizing agent
- D Extreme health hazard
Correct answer: Extreme health hazard
The NFPA diamond uses the blue quadrant for health. A scale of 0 to 4 is used, where 0 is a minimal hazard and 4 indicates that even short exposure could cause death or major residual injury.
Why is eating and drinking strictly prohibited in the science laboratory?
- A Chemicals can be accidentally ingested via contaminated hands or surfaces
- B Food particles falling into the apparatus can contaminate samples and ruin an experiment
- C Crumbs may attract insects that interfere with equipment
- D Fumes in the laboratory air make food taste bitter and unpleasant
Correct answer: Chemicals can be accidentally ingested via contaminated hands or surfaces
Laboratory surfaces often have invisible chemical or biological residues. Eating in the lab provides a direct pathway for these contaminants to enter the body through ingestion.
What is the correct procedure for disposing of broken glass in the lab?
- A Place it in the regular trash can along with the paper waste
- B Rinse it thoroughly and place it in the glass recycling bin with other glassware
- C Leave it on the floor for the janitorial staff to sweep up later
- D Place it in a designated, puncture-resistant 'Broken Glass' container
Correct answer: Place it in a designated, puncture-resistant 'Broken Glass' container
Broken glass can easily puncture standard trash bags and injure waste handlers. A dedicated rigid container ensures that sharp edges are contained and handled safely.
Before using a centrifuge, you must ensure that the tubes are 'balanced.' This means:
- A Tubes of equal mass are placed directly opposite each other
- B The tubes are all from the same manufacturer
- C The lid of each tube is screwed on tightly before spinning
- D The centrifuge is plugged into a properly grounded electrical outlet
Correct answer: Tubes of equal mass are placed directly opposite each other
An unbalanced centrifuge can vibrate violently at high speeds, leading to equipment failure or mechanical hazards. Balancing ensures that the center of mass remains at the axis of rotation.
What should be done with leftover chemicals after an experiment is finished?
- A Pour them back into the original stock bottle to avoid wasting money
- B Pour them down the sink and flush with plenty of running water
- C Leave them in the beaker on the bench for the next class
- D Dispose of them in the designated waste containers as instructed
Correct answer: Dispose of them in the designated waste containers as instructed
Never return chemicals to stock bottles as this can contaminate the entire supply. Proper disposal in waste containers prevents hazardous chemical reactions in the plumbing and environmental pollution.
A 'Corrosive' substance is one that:
- A Destroys or irreversibly damages living tissue on contact
- B Explodes violently when shaken or struck
- C Ignites spontaneously at room temperature
- D Causes cancer in humans after prolonged or repeated exposure
Correct answer: Destroys or irreversibly damages living tissue on contact
Corrosives, such as strong acids and bases, chemically destroy skin, eyes, and respiratory tracts upon contact. Protective gear like gloves and aprons are essential when handling them.
Which of the following is the best footwear for working in a science laboratory?
- A Sandals or flip-flops
- B Open-toed high heels
- C Canvas sneakers with mesh holes for ventilation
- D Closed-toe shoes that cover the entire foot
Correct answer: Closed-toe shoes that cover the entire foot
Closed-toe shoes protect the feet from falling glass, heavy objects, and chemical spills. Mesh or canvas shoes are less ideal than leather or synthetic materials because they can absorb spilled liquids.
In a lab, 'PPE' stands for:
- A Personal Protective Equipment
- B Public Physics Education
- C Primary Particle Examination
- D Pressurized Particle Enclosure
Correct answer: Personal Protective Equipment
PPE refers to items like gloves, safety glasses, lab coats, and face shields. It is the final line of defense to protect the individual from hazards that cannot be eliminated by engineering or administrative controls.
What is the first thing you should do if a fire breaks out in the laboratory?
- A Notify the instructor and alert others in the area
- B Try to extinguish it immediately by yourself with an extinguisher
- C Run out of the building without saying anything
- D Open all the windows to let the smoke out
Correct answer: Notify the instructor and alert others in the area
Communication is the most critical first step in an emergency. Ensuring that the instructor is aware and that everyone is alert allows for an organized evacuation or a professional response with fire-fighting equipment.