Laboratory and Practical Skills — Short Questions

Example of corrosive chemicals are mineral aids including HF, caustic alkalies, acetic acid (glacial) etc.

i. Obtain prior approval from your teacher
ii. Always use smallest quantity of the chemicals.
iii. Always conduct experiment in fume hood.
iv. Remove all other chemicals and apparatus around you.
v. Inform other people working with you.

When chemical reactions are not properly performed, they may cause fires, explosions as they may evolve dangerous gases. These reactions may result to an extreme damage to life and property.

i. Stay inside as walls and ceilings can protect you from radiation fall out.
ii. Never operate equipment that produces radiation without sufficient training.

Asphyxiation Hazards It is a type of hazard in which a gas or vapour can cause unconscious or death through suffocation.

Examples of chemical asphyxiants are hydrogen cyanide, carbon monoxide, nitrogen, argon, helium, methane and carbon dioxide etc.

Several signs and symbols are posted in different areas of the lab and bottles containing hazardous chemicals. Because these signs indicate that specific precautions must be observed according to the requirements sign posted there. If you see such signs, you must be alert and take extra care to maintain safety in that area.

The following points should be kept in mind to cope with the emergency situation:
i. Stay calm and do not panic.
ii. Alert people in the area to evacuate.
iii. In case of fire, close doors to confine fire. Use fire extinguisher to put down the fire.
iv. Call and assist emergency staff.

Students should make themselves aware of the actions that need to be taken in case of an emergency in a laboratory or if a person is affected. For this purpose periodic drills should be held with compulsory participation. Students should not only have been given lectures but involve them practically to handle the emergency situations. During drill firefighting and other equipments must be checked whether they are in proper working order or not.

Flammable liquids should not be stored in refrigerators for several reasons:

• Refrigerators can trap flammable vapors, creating a risk of explosion if there's a spark from electrical components.
• Refrigerators offer contain material like plastic-rubber and insulation that can be damaged or degraded by flammable liquids.
• Many safety regulations prohibit storing flammable materials in standard refrigerators to ensure safety.

Always wear safety goggles over your contact lenses to protect your eyes from any splashes.

• If there's a risk of chemical exposure, it's better to wear protective eyewear like goggles instead of depend solely on contact lenses.
• Ensure your contact lenses are comfortable and won't cause irritation, especially if you'll be working long hours in the lab.
• Maintain good hygiene by washing your hands before handling your contact lenses to prevent any contamination.
• Know the lab's emergency procedures in case of eye exposure to chemicals and always have an eyewash station nearby.

If you ever come across any chemical that you suspect to explode, do not attempt to move the container to avoid shock. Explosive chemicals are likely to explode under these circumstances:

• High temperatures can trigger reactions.
• Physical force can cause explosions.
• Mixing with incompatible substances can be dangerous.
• High pressure can lead to explosive decompression.
• Storing in unsuitable conditions increases risks.

Acids and bases are first neutralized followed by sewer disposal. Hazardous waste material is transported to hazardous waste disposal site. To dispose of acid and alkali waste safely:

• Use sodium bicarbonate for acids or vinegar for alkalis to neutralize the waste.
• Add plenty of water to dilute the neutralized waste.
• Ensure the pH is neutral (around pH 7) using pH paper.
• Check local disposal regulations for hazardous waste.

The warning sign "caution" conveys a message of alertness to potential hazards. It indicates that there may be a risk or danger present and individuals should be careful and attentive in that area.

Some explosive chemicals include

• Picric acid
• 2,4-dinitrophenyl hydrazine
• Benzoyl peroxide
• Nitrocellulose

Emergency drills should be compulsory because they ensure everyone knows how to respond in an emergency, reduce panic, promote teamwork, identify weaknesses in plans, and often meet legal requirements. Making them mandatory enhances overall safety and preparedness.

A chemistry laboratory is a place where a student is trained to observe the physical and chemical characteristics of substances.

Reactions of Students i. Before starting the laboratory work, a student should get himself familiarized with the layout of the laboratory and various fittings provided in the laboratory table as well as the side shelves.
ii. Students are expected to conduct themselves in a responsible manner at all times in the lab.
iii. They are advised not to work alone in the lab.
iv. Experiments should be performed in the presence of lab instructor and other laboratory staff.

i. Do not pour chemicals down the drains and do not utilize the sewer for chemical waste disposal.
ii. Keep all sink traps and floor drains clean.
iii. Laboratory chemical waste can be disposed of in sewer or trash bin if they are non-hazardous materials.
iv. Acids and bases are first neutralized followed by sewer disposal.

Explosive Chemicals Chemicals that cause a sudden release of pressure, gas and heat when they experience sudden shock are called explosive chemicals.

Examples of chemicals which are expected to explode are picric acid, 2,4-dinitrophenyl hydrazine, benzoyl peroxide, nitrocellulose etc.

Flammable chemicals or mixtures are those which have a flashpoint around room temperature. Examples of flammable compounds are ethers, methylated spirit, benzene, acetone, petrol etc.

Disadvantages of Corrosive Chemical i. Corrosive chemicals attack living tissues when they come in contact with them.
ii. They can be in the form of solids, liquids or gases. Such chemicals attack skin, eyes and respiratory tract and in the intestine as well.
iii. Whenever you work with corrosive chemicals, wear splash goggles instead of safety glasses and use a face shield.

A toxic chemical is a poisonous material which is capable of causing serious health problems.

Example Mercury, benzene, chlorine, pesticides, ammonia, hydrogen cyanide are some examples of toxic chemicals.

The following safety instructions may be ensured in case you intend to work with toxic chemicals.
i. Wear gloves, masks or other protective devices.
ii. Keep the work area well ventilated.
iii. Keep the toxic chemicals in original container.
iv. Wash your hands with soap and water after you finished.

The reactivity of chemicals is vital for the production of many chemicals, pharmaceutical and food products which are in our daily use.

Hazards When chemical reactions are not properly performed, they may cause fires, explosions as they may evolve dangerous gases. These reactions may result to an extreme damage to life and property.

Examples of reactive chemicals are calcium hydride Na, Li, azides, picric acid, AlCl₃, benzoyl peroxide etc.

i. Handle reactive chemicals with utmost care. Segregate these from other chemicals while storage.
ii. Appropriate measures should be taken before performing reactions with reactive chemicals. Utilize shield and heavy gloves.
iii. Minimize the quantity required for experiment.
iv. Glass equipment must be shielded by wrapping with tape.

i. When a person is exposed to a high dose of radiation, it can damage the functioning of tissues and organs and can cause vomiting, radiation burns, hair loss and radiation syndrome.
ii. Radioactive materials that emit alpha and beta particles inflict extreme damage when inhaled or injected. Gamma rays cause external injuries.
iii. Medical x-rays produce ionizing radiation which can affect living tissues.

i. Store and use asphyxiant chemicals in well-ventilated areas with plenty of air.
ii. Wear a full lab coat, wear glasses and standard gloves, long trousers and closed-toed shoes.
iii. Dispose off the waste strictly according to the instructions.
iv. If exposed to such chemicals wash the exposed part with running water and seek medical attention.

Corrosive chemicals attack living tissues when they come in contact with them. They can be in the form of liquids or gases. Such chemicals attack skin, eyes, respiratory tract and in the intestine as well.

Example of corrosive chemicals are mineral acids including HF, caustic alkalis, acetic acid (glacial) etc.

Safety Precautions i. Whenever you work with corrosive chemical, wear splash goggles instead of safety glasses and use a face shield.
ii. Safety glasses and use a face shield.
Corrosive chemicals must be used in a fume cupboard to avoid breathing corrosive vapours.
iii. (While mixing concentrated acids with water, always add acid slowly to water and not vice versa.)
iv. Ensure eyewash and emergency shower is available.

Toxic Chemical A toxic chemical is a poisonous material which is capable of causing serious health problems.

Examples Mercury, benzene, chlorine, pesticides, ammonia, hydrogen cyanide are some examples of toxic chemicals.

Safety Instruction i. Wear gloves, masks or other protective devices.
ii. Keep the work area well ventilated.
iii. Keep the toxic chemicals in original container.
iv. Do not work alone.

Reactivity The reactivity property of chemicals is vital for the production of many chemicals, pharmaceutical and food products which are in our daily use.

Examples of reactive chemicals are calcium hydride Na, Li, azides, picric acid, AfCl, benzoyl peroxide etc.

Safety instructions i. Handle reactive chemicals with utmost care. Segregate these from other chemicals while storage.
ii. Appropriate measures should be taken before performing reactions with reactive chemicals. Utilize shield and heavy gloves.
iii. Minimize the quantity required for experiment.

When a person is exposed to a high dose of radiation, it can damage the functioning of tissues and organs and can cause vomiting, radiation burns, hair loss and radiation syndrome.

Radioactive materials that emit alpha and beta particles inflict extreme damage when inhaled or injected. Gamma rays cause external injuries. Medical x-rays produce ionizing radiation which can affect living tissues.

Safety instructions i. Keep radioactive sources shielded.
ii. Avoid prolonged exposures to the radiation.
iii. Stay inside walls and ceiling that can protect you from radiation fall out.
iv. Never operate equipment that produces radiation without sufficient training.

Asphyxiation it is a type of Hazard in which a gas or vapour can cause unconscious or death through suffocation.

Example Examples of chemical asphyxiants are Hydrogen cyanide. Carbon monoxide, Nitrogen, Argon, Helium, Methane and Carbon dioxide etc.

Safety instructions i. Store and use asphyxiant chemicals in well-ventilated areas with plenty of air
ii. Wear a full lab coat, wear glasses and standard gloves, long trousers and closed-toed shoes.
iii. Dispose off the waste strictly according to the instructions.
iv. If exposed to such chemicals wash the exposed part with running water and seek medical attention.

Personal protective equipment should be made available to students to face any emergency situation which may arise in the lab. They are also useful to reduce exposures to hazardous chemicals.

Example Proper protective equipment include such items as lab coat, protective glasses, face shields, apron, boots and hearing protection.

Chemical laboratories using such materials which are likely to catch fire during experiments must have a portable fire extinguisher. This equipment can quickly be used to control a small fire if it is applied by a student individually.

If a fire occurs due to short-circuiting, here's how to handle the emergency situation:

• It's crucial to remain calm to think clearly and act effectively.
• Immediately yell "Fire!" to alert everyone in the vicinity. This helps ensure that everyone is aware of the situation.
• If it's safe to do so, call emergency services or have someone else do it. Provide them with the necessary information about the location and nature of the fire.
• Follow the established evacuation routes. Do not use elevators, as they may become inoperable. Help others if you can, but do not put yourself in danger.
• If the fire is small and you have been trained to use a fire extinguisher, you can attempt to put it out. Use the PASS technique: o Pull the pin. o Aim the nozzle at the base of the fire. o Squeeze the handle. o Sweep side to side.
• Do not re-enter the building until emergency services declare it safe.

In a fume cupboard (or fume hood), you should carry out the following types of reactions:

• Reactions involving volatile chemicals that can release harmful vapours or gases should be conducted in a fume cupboard to prevent inhalation.
• Any reactions that involve toxic or hazardous substances, such as heavy metals or certain organic solvents, should also take place in a fume cupboard to minimize exposure.
• When working with corrosive materials, such as strong acids or bases, a fume cupboard is essential to protect against harmful splashes and vapours.
• If a reaction is highly exothermic and could produce fumes or gases, it's safer to conduct it in a fume cupboard.

Here are two suggestions to improve safety in the lab:

• Conduct regular safety training sessions for all lab personnel. This training should cover proper handling of chemicals, use of safety equipment, and emergency procedures. Ensuring everyone is knowledgeable about safety protocols can significantly reduce the risk of accidents.
• Ensure that all chemicals are properly labeled with clear hazard information and stored according to their compatibility. This includes using appropriate containers and keeping reactive substances away from each other. Proper labeling and storage help prevent accidental mixing and exposure.

The page shows two warning symbols:
1. A triangle with a figure crouching and the text "Danger - Risk of Asphyxiation"
2. A triangle with radiation symbols (three dots arranged in a circle pattern) and the text "RADIATION HAZARD"

Sudden shock can cause some chemicals to explode for a couple of reasons:

• Shock can provide enough energy to break chemical bonds, leading to rapid reactions that release energy explosively.
• If the shock causes a rapid change in temperature or pressure in a closed container, it can exceed the container's limits, resulting in an explosion.