DEPARTMENT OF CHEMISTRY
TEACHING LAB EXPERIMENT RISK ASSESSMENT FORM
This form must be completed jointly by the Lab Officer in charge and the Lecturer in charge. A
hardcopy of the completed form should be kept in a file together with the Project Risk
Assessment.
Name of Lecturer in Charge
Name of Lab Officer in Charge
Module / Expt No.
A/P Jaenicke Stephan
Activity being assessed:
Toh Soh Lian
CM2167/Expt. 2
Potentiometric Analysis : pK of a Weak Acid
To identify an unknown organic acid by its melting point and pKa.
Known or expected hazards associated with the activity:
Hazards of reagents, solvents and known reaction products.
State each substance and the approximate amounts to be used/produced.
List of activities involved in this experiment which inevitably entail risks. The following are the
activities being use:
1)
Glass Apparatus. Refer to prepared risk assessment on Use of Glassware.
2)
Hotplate / Magnetic Stirrer, Water Bath, IR lamp and Melting Point Instrument. Refer to
prepared risk assessment on Use of Laboratory Heating Equipment.
3)
Disposal Glass Pasteur. Refer to prepared risk assessment on Use and Disposal of
"Sharps".
4)
Electricity. Refer to prepared risk assessment on Use of Standard Electrical Equipment.
p-Nitro Benzoic Acid: about 4g.
Harmful.
Benzoic Acid: about 4g.
Harmful and irritating.
m-Nitro Benzoic Acid: about 4g.
No information available.
2-Amino Benzoic Acid: about 4g.
Irritating.
Anisic Acid: about 4g.
Not hazardous product.
2-Bromo Benzoic Acid: about 4g.
Irritating
o-Toluic Acid: about 4g.
Page 1 of 10
Printed on: 12 February 2016
Irritating.
m-Toluic Acid: about 4g.
Harmful.
Oral: Behavioral: Muscle weakness. Lungs, Thorax, or Respiration: Respiratory depression.
Gastrointestinal: Nausea or vomiting.
Intraperitoneal: Behavioral: Rigidity (includes catalepsy). Behavioral: Muscle contraction or
spasticity.
Buffer Solution (pH 4): about 50ml.
No hazardous product.
Buffer Solution (pH 7): about 50ml.
No hazardous product.
95% Ethanol: about 300ml
Danger! Poison! Flammable liquid & vapor. Vapor may cause flash fire. May be fatal and may
cause blindness. If swallowed cannot be made non-poisonous.
defect hazard. Contains
material which can cause birth defect. Contains material which causes damage to the following
organs: blood, kidneys, reproductive system, liver, gastrointestinal tract, respiratory tract, skin,
central nervous system, eye lens or cornea.
Highly flammable & explosive in presence of open flames, sparks and static discharge, of heat,
of oxidizing materials. Flammable & explosive in presence of shocks.
Phenolphthalein: drop wise
Flammable.
Potassium Acid Phthalate: about 3-4g.
No hazardous product.
0.1M Sodium Hydroxide Solution: about 50ml.
CAUTION ! Causes respiratory tract, eye and skin irritation. Routes of Entry: Dermal contact,
eye contact, inhalation, ingestion.
*amount stated are computed for the whole experiment.
Incompatible materials (special precautions):
p-Nitro Benzoic Acid:
Conditions to be avoided: Strong heating (decomposition).
Substances to be avoided: Potassium hydroxide.
Further information: Sublimable.
Page 2 of 10
Printed on: 12 February 2016
Benzoic Acid:
Conditions to be avoided: Temperatures above melting point.
Substances to be avoided: Fluorine, oxygen, bases, oxidizing agent.
Further information: Sublimable.
m-Nitro Benzoic Acid:
Materials to Avoid: Strong oxidizing agents, Strong bases.
Hazardous Decomposition Products: Carbon monoxide, Carbon dioxide, Nitrogen oxides.
2-Amino Benzoic Acid:
Conditions to be avoided: Heating.
Substances to be avoided: Strong oxidizing agents, strong bases.
Further information: Light-sensitive; dust explosion possible.
Anisic Acid:
Conditions to Avoid: Strong heating.
2-Bromo Benzoic Acid:
Materials to Avoid: Strong oxidizing agents.
Hazardous Decomposition Products: Carbon monoxide, Carbon dioxide, Hydrogen bromide
gas.
o-Toluic Acid:
No information available.
m-Toluic Acid:
Materials to Avoid: Strong oxidizing agents, Strong bases.
Hazardous decomposition products: Hazardous Decomposition Products: Carbon monoxide,
Carbon dioxide.
Buffer Solution (pH 4 & pH 7):
Substances to Avoid: The generally known reaction partners of water.
95% Ethanol:
Highly reactive with oxidizing agents. Slightly reactive to reactive with metals, acids.
Phenolphthalein:
Conditions to Avoid: Heating.
Further information: Inflammable; explosible with air in a vaporous/gaseous state.
Potassium Acid Phthalate:
Page 3 of 10
Printed on: 12 February 2016
No information available.
0.1M Sodium Hydroxide Solution:
Reactive with metals, acids. Incompatible with organic halogens, nitro and chloro organic
compounds, peroxide , Aluminium , Tin , Zinc , strong acids.
The risk of injury and its severity likely to arise from these hazards:
p-Nitro Benzoic Acid:
Eye Contact: Slight irritations.
Inhalation: Irritations of mucous membranes, coughing, and dyspnoea.
Ingestion: Irritaions of mucous membranes in the mouth, pharynx, oesophagus and
gastrointestinal tract.
Other notes: The following applies to aromatic nitro compounds in general: systemic effect:
methaemoglobinaemia with headache, cardiac dysrhythmias, drop in blood pressure, dyspnoea,
and spasms; principal sign: cyanosis (blue discoloration of the blood).
Benzoic Acid:
Eye Contact: Severe irritations.
Skin Contact: Slight irritations..
m-Nitro Benzoic Acid:
Skin Contact: May cause irritation.
Skin Absorption: May be harmful.
Eye Contact: May cause irritation.
Inhalation: May be harmful. Material may be irritating to mucous membranes and upper
respiratory tract.
Ingestion: May be harmful.
2-Amino Benzoic Acid:
Eye Contact: Irritations.
Anisic Acid:
Hazardous properties cannot be excluded, but are unlikely when the product is handled
appropriately.
2-Bromo Benzoic Acid:
Inhalation: Material is irritating to mucous membranes and upper respiratory tract.
Multiple Routes: May be harmful by inhalation, ingestion, or skin absorption. Causes eye and
skin irritation.
o-Toluic Acid:
Page 4 of 10
Printed on: 12 February 2016
Eye Contact: Irritations.
m-Toluic Acid:
Route of Exposure: Multiple Routes: May be harmful by inhalation, ingestion, or skin absorption.
May cause irritation.
Inhalation of vapours: Slight mucosal irritations. Risk of absorption.
Ingestion of large amounts: Nausea, vomiting, diarrhoea.
Buffer Solution (pH 4 & pH 7):
Hazardous properties cannot be excluded, but are relatively unlikely because of the low
concentration of the dissolved substances and to the data of the components, when the product
is handled appropriately.
95% Ethanol:
Eye Contact: Hazardous (irritant). Inflammation of the eye is characterized by redness,
watering, and itching.
Skin Contact: Hazardous (permeator, irritant). Skin inflammation is characterized by itching,
scaling, reddening, or, occasionally, blistering.
Inhalation: Hazardous (lung irritant)
Ingestion: Extremely hazardous. May be fatal or cause blindness if swallowed.
Phenolphthalein:
Eye Contact: Slight iirritations
Skin Contact: After long-term exposure to the chemical – dermatitis.
Inhalation of vapours: Slight mucosal irritations. Risk of absorption.
Ingestion of large amounts: Nausea, vomiting, diarrhoea.
Systemic effects: Euphoria.
After absorption of large quantities: Dizziness, Inebriation, Narcosis, Respiratory Paralysis.
Potassium Acid Phthalate:
Skin & Eye Contact: Slight irritations
0.1M Sodium Hydroxide Solution:
Skin Contact: Irritant. Skin inflammation is characterized by itching, scaling, reddening, or,
occasionally, blistering.
Eye Contact: Irritant. Inflammation of the eye is characterized by redness, watering, and itching.
Ingestion: May be hazardous.
Inhalation: Hazardous (lung irritant).
Aggravated by Overexposure: Contact with spray mist may produce chronic eye irritation and
severe skin irritation and may produce respiratory tract irritation leading to frequent attacks of
Page 5 of 10
Printed on: 12 February 2016
bronchial infection.
Who is at risk?
Persons handling the materials and as well as those present in the vicinity.
Measure to be taken to reduce the level of risk:
Proper laboratory attire and safety measures must always be used in order to reduce the level
or risk. Material should be handled or transferred in an approved fume hood or with adequate
ventilation Wash thoroughly after handling. Do not take internally. Eye wash and safety
equipment should be readily available.
Eye protection: Chemical safety goggles.
Hand protection: Gloves.
Please
refer
to
PSSO
Safety
Information
Centre
website
on
safety
measures:
http://www.chemistry.nus.edu.sg/PSSO/Safety.htm.
Training prerequisites:
This assessment should be read by everyone who will be using the above mentioned
chemicals. Please refer to Completed Risk Assessment forms on Common Activities:
http://www.chemistry.nus.edu.sg/PSSO/Safety/Risk/risk.htm#Common.
Level of risk remaining:
Constant vigilance is required by the users.
Emergency action if :
Spill:
p-Nitro Benzoic Acid, Benzoic Acid, Anisic Acid & o-Toluic Acid:
Avoid generation of dusts; do not inhale dusts. Ensure supply of fresh air in enclosed rooms. Do
not allow to enter sink. Take up dry. Forward for disposal. Clean up affected area.
m-Nitro Benzoic Acid:
Exercise appropriate precautions to minimize direct contact with skin or eyes and prevent
inhalation of dust. Sweep up, place in a bag and hold for waste disposal. Avoid raising dust.
Ventilate area and wash spill site after material pickup is complete.
2-Amino Benzoic Acid:
Avoid substance contact. Avoid generation of dusts; do not inhale dusts. Ensure supply of fresh
air in enclosed rooms. Do not allow to enter sink. Take up dry. Forward for disposal. Clean up
affected area.
2-Bromo Benzoic Acid & m-Toluic Acid:
Wear chemical safety goggles, rubber boots and rubber gloves. Sweep up, place in a bag and
hold for waste disposal. Avoid raising dust. Ventilate area and wash spill site after material
pickup is complete.
Page 6 of 10
Printed on: 12 February 2016
Buffer Solution (pH 4 & 7), Phenolphthalein:
Do not inhale vapours/aerosols. Do not allow to enter sink. Take up with liquid-absorbent
material. Forward for disposal. Clean up affected area.
95% Ethanol:
Small Spill & Leak: Dilute with water and mop up, or absorb with an inert dry material and place
in an appropriate waste disposal container.
Large Spill & Leak: Keep away from heat and sources of ignition. Stop leak if without risk. Cover
with DRY sand or other non-combustible material. Do not touch spilled material. Prevent entry
into sink. Call for assistance on disposal.
Potassium Acid Phthalate:
Avoid generation of dusts; do not inhale dusts. Do not allow to enter sink.
0.1M Sodium Hydroxide Solution:
Small Spill and Leak: Dilute with water and mop up, or absorb with an inert dry material and
place in an appropriate waste disposal container.
Large Spill and Leak: Stop leak if without risk. Absorb with DRY sand or other non-combustible
material. Do not touch spilled material. Prevent entry into sink. Call for assistance on disposal.
Fire:
p-Nitro Benzoic Acid:
Suitable extinguishing media: Water CO2, foam, powder.
Special risks: Combustible. Development of hazardous combustion gases or vapours possible
in the event of fire. The following may develop in event of fire: nitrogen oxides.
Other information: Contain escaping vapours with water.
Benzoic Acid:
Suitable extinguishing media: Water CO2, foam, powder.
Special risks: Combustible. Development of hazardous combustion gases or vapours possible
in the event of fire.
Other information: Cool container with spray water from a save distance. Contain escaping
vapours with water.
m-Nitro Benzoic Acid:
Extinguishing media: Water spray. Carbon dioxide, dry chemical powder, or appropriate foam.
Specific hazard(s): Emits toxic fumes under fire conditions.
2-Amino Benzoic Acid:
Suitable extinguishing media: Foam, powder.
Page 7 of 10
Printed on: 12 February 2016
Special risks: Combustible. Formation of hazardous combustion gases or vapours possible in
event of fire. The following may develop in event of fire: nitrous gases.
Other information: Contain escaping vapours with water.
Anisic Acid:
Suitable extinguishing media: Water CO2, foam, powder.
Special risks: Combustible. Development of hazardous combustion gases or vapours possible
in the event of fire.
2-Bromo Benzoic Acid:
Extinguishing media: Water spray. Carbon dioxide, dry chemical powder, or appropriate foam.
Specific Hazard(s): Emits toxic fumes under fire conditions.
Exposure hazard(s) material: Irritant.
o-Toluic Acid:
Suitable extinguishing media: Water CO2, foam, powder.
Special risks: Combustible. Development of hazardous combustion gases or vapours possible
in the event of fire. Danger of dust explosion.
m-Toluic Acid:
Extinguishing media: Water spray. Carbon dioxide, dry chemical powder, or appropriate foam.
Specific Hazard(s): Emits toxic fumes under fire conditions.
Exposure Hazard(s): Material: Harmful solid.
Buffer Solution (pH 4 & pH 7):
Suitable extinguishing media: In adaption to materials stored in the immediate neighbourhood.
Special risks: Non-combustible.
95% Ethanol:
Small Fire: Use DRY chemical powder.
Large Fire: Use alcohol foam, water spray or fog. Cool containing vessels with water jet in order
to prevent pressure build-up, auto ignition or explosion.
Phenolphthalein:
Suitable extinguishing media: CO2, foam, powder.
Special risks: Combustible. Vapours heavier than air. Formation of explosible mixtures possible
with air. Keep away from sources of ignition.
Other information: Cool container with spray water from a save distance. Take measures to
prevent electrostatic charging.
Page 8 of 10
Printed on: 12 February 2016
Potassium Acid Phthalate:
Suitable extinguishing media: In adaption to materials stored in the immediate neighbourhood.
Special risks: Combustible.
0.1M Sodium Hydroxide Solution:
Fire Fighting Media: Use extinguishing media suitable for surrounding materials.
Special Remarks on Explosion Hazards: Can react with certain metals to release explosive
hydrogen gas.
Is the experiment suitable for out-of-hours operation ?
Yes
No
References if any:
http://chemdat.merck.de/cdrl/catalog/standard/en/index.html (Cat. No. : 800646)
http://chemdat.merck.de/cdrl/catalog/standard/en/index.html (Cat. No. : 100136)
http://www.sigma-aldrich-sea.com/MSDS/18/185329A.pdf
http://chemdat.merck.de/cdrl/catalog/standard/en/index.html (Cat. No. : 820112)
http://chemdat.merck.de/cdrl/catalog/standard/en/index.html (Cat. No. : 805971)
http://www.sigma-aldrich-sea.com/MSDS/16/16320F.pdf
http://chemdat.merck.de/cdrl/catalog/standard/en/index.html (Cat. No. : 821901)
http://www.sigma-aldrich-sea.com/MSDS/89/89892F.pdf
http://chemdat.merck.de/cdrl/catalog/standard/en/index.html (Cat. No. : 109435)
http://chemdat.merck.de/cdrl/catalog/standard/en/index.html (Cat. No. : 109439)
http://www.emdchemicals.com/analytics/doc/msds/msds-display.asp?materialid=EX0280
http://chemdat.merck.de/cdrl/catalog/standard/en/index.html (Cat. No. : 107227)
http://chemdat.merck.de/cdrl/catalog/standard/en/index.html (Cat. No. : 104874)
http://www.emdchemicals.com/analytics/doc/msds/msds-display.asp?materialid=SX0607C
Signature of Lab Officer in Charge:………………………………………………………………..
Date:…………………………
Signature of Lecturer in Charge:………… ……………………………………..
Date:… ……………………..
Prepared Risks Assessments for standard equipment and operation are with the kind permission of Dr. Ken MacNeil,
School of Chemistry, University of Bristol.
Page 9 of 10
Printed on: 12 February 2016
Activity being assessed:
Note any activity to be used which entail risk (e.g. use of glass vacuum apparatus, high pressures, high
voltage, radiation, high temperatures). Give reference to any special protocols to be followed, and if
appropriate attach copies to the risk assessment form. State any additional precautions taken to minimise
risk.
Known or expected hazards associated with the activity:
FOR EACH CHEMICAL, read the MSDS and note:a) Particular hazards (e.g. highly toxic, carcinogenic, corrosive, flammable, pyrophoric, explosive, volatile,
dust hazard). Note any dangerous combinations of properties (e.g. volatile and toxic).
b) Requirements for safe handling (e.g. fume cupboard, inert atmosphere, low temperature).
c) How to dispose of residuals
 Dispose to drain, with water dilution
 Neutralise, then to drain with suitable dilution
 To flammable liquid waste receptacle
 To non-flammable liquid waste receptacle
 Keep for recovery/recycling
 Keep for special disposal later (e.g. heavy metals)
 Double bag and dispose to dry waste
 Special procedure (specify)
Incompatible materials (special precautions)
Note any dangerously incompatible materials and hazards arising from contact of any reagents and
substances used with common materials such as paper, benches, hoses, etc.
Measures to be taken to reduce the level of risk
Include hazards of previously unknown products.
Location of work – laboratory, open bench, fume cupboard
Level of risk remaining:
Likelihood and consequences of any accident or unforeseen events whilst carrying out the activity. When
this has been done, choose the appropriate procedure:a) Close supervision and/or attendance of trained first-aider needed.
b) Specific approval of supervisor needed.
c) Training is needed prior-to or during the operations specified.
d) Training is complete and only general laboratory competence required.
e) No risk perceived.
Emergency action:
a) Any special requirements to deal with accidental spillage or leakage.
b) What to do in the event of accidental exposure (skin contact, inhalation, etc.).
Page 10 of 10
Printed on: 12 February 2016