3-Methylbutanol
(iso-amyl alcohol)
F-, Xn
Y11
N12
S3
(FC)
3-Methylbutyl ethanoate
(iso-amyl acetate)
F-
Y12
N13
S4
(FC)
N-methylcarbamide
(Methylurea)
Xn
Y12
N13
S5
Suitable for use on small scale as solvent.
Methyl chloride
see
Chloromethane
Methylchloroform
see
1,1,1-trichloroethane
Methyl cyanide
see
Ethanenitrile
see
Dichloromethane
Methylene blue
solid
solution
Xn
Teacher/Technician
Y7
N8
S1
F, Xi
Y11
Methylene dichloride
Methyl ethanoate
(acetate)
N12
S4
(FC)
Methyl formate
see
Methyl methanoate
Methyl ethyl ketone (M.E.K.)
see
Butanone
Methyl iodide
see
Iodomethane
Methyl methacrylate
see
Methyl 2-methylpropenoate
Methyl methanoate
(formate)
F+, Xi
Y11
(N13)
S4
(FC)
Methyl 2-methylpropenoate
(Methyl methacrylate, Perspex monomer)
F, Xi, Sen
(Y12)
(N13)
(S6)
(FC)
1 to 20%
Methyl Orange
solid
solution
0.04%
2-Methylpropan-2-ol
(tert-butyl alcohol)
Xi, Sen
T
Teacher/Technician
F
Y7
N8
S1
F, Xn
(Y11)
(N12)
S5
Solution prepared by teacher or technician.
Methylurea
Millon's Reagent
(FC)
see
T+, C, N
NR
NR
The substance is a known skin sensitiser and may also be a respiratory sensitiser. Because of
this and the fact that the vapour is lachrymatory, the depolymerisation of perspex is best
carried out in a fume cupboard as a demonstration.
The polmerisation reaction initiated with is very exothermic if more than a very small
quantity of didodecanoyl peroxide catalyst is used. As supplied the material has a stabiliser
added and this needs to be removed by shaking with dilute sodium hydroxide before
polymerisation is attempted.
(S6)
© ASE 2003 (adapted from Safety in Science Education, 1996 (HMSO) and Topics in Safety, 1988 & 1982
N-methylcarbamide
This material contains toxic materials as well as concentrated acid. Its use is best avoided in
schools as there are less hazardous alternatives such as Albustix, Sakaguchi test or Cole's
modification of Millon's reagent which provide safer alternatives. See HazChemMan CD2
(SSERC) or Hazcards (CLEAPSS).
For abbreviations see Introduction
Millon's Reagent,
Cole's modification
T+, C, N
(Y9)
(N10)
(S5)
Although this material contains toxic material as well as concentrated acid it is safer than
traditional Millon's reagent. See HazChemMan CD2 (SSERC) or Hazcards (CLEAPSS).
Molybdenum,
Low hazard
Y9
N10
S4
Avoid inhaling any dust if a molydenum alloy is machined or sanded.
Naphtha
F, Xn
Teacher/Technician
Naphthalen-1-amine
(1-naphthylamine)
Xn, N
Banned
Old samples of the 1- isomer are often impure and may contain traces of the 2- isomer
which is banned. Banned by virtue of possible impurity.
Naphthalen-2-amine
(2-naphthylamine)
T, N, Carc 1
Banned
Known carcinogen banned by COSHH.
Naphthalene
F-, Xn, N
Y12
N13
S6
Naphthalen-1-ol
(α-naphthol)
Xn
Y12
N13
S6
Naphthalen-2-ol
(β-naphthol)
Xn, N
Y12
N13
S6
Nessler's Reagent
T+, C, N
(Y12)
(N13)
(S5)
Xn, Carc 3, Sen
(Y12)
(N13)
(S6)
solid
Nansa acid
Nickel ammonium sulfate
Nickel, dust
see
Dodecylbenzenesulfonic acid
FC
This material is not the best for storage of alkali metals as naphthas vary in toxicity owing to
a wide range of compounds; some of these will be Category 2 Carcinogens by the inhalation
route. Liquid paraffin is much safer.
(FC)
These materials should not be nitrated. They are safe to use in the preparation of azo dyes
but these must not be isolated as some insoluble azo-dyes have been shown to be
carcinogenic. It is better to use sulfonated naphthols as these form water-soluble azo dyes.
Old samples of the naphthalen-1-ol may contain 2-naphthylamine the presence of which is
very hazardous and only samples of known purity > 99% can be considered safe to use.
The mixture contains potassium iodide, mercury iodide and sodium hydroxide.
Alternatively use water test strips.
see
Ammonium nickel(II) sulfate
The dust is a carcinogen by inhalation and the metal is also a sensitiser, causing nickel rash.
However nickel sheet and wire are safe to handle and the metal is commonly used for
jewellery and coins.
Nickel dusts used as hydrogenation catalysts can spontaneously ignite if exposed to air; after
hydrogenating an oil, store in a lump of the solidified fat.
Nickel salts in general
They are carcinogenic by inhalation. The dust is a major problem and care needs to be taken
as sensitisation to the material may occur both by inhalation and by skin contact. Take care
with reactions which produce an aerosol, eg dissolving the carbonate in dilute acid or
electrolysis.
solid and solutions > 25%
solution
10 to 25%
Xn, N, Carc 3(inhal), Sen
N, Carc 3(inhal), Sen
Y12
Y9
N13
N10
(S6)
(S2)
solution
N, Sen
Y9
N10
S4
1% to 10%
Naphthalene is readily absorbed by inhalation and via the skin and is a suspect carcinogen;
see Topics 12.2.5. For cooling curves safer alternatives include hexadecan-1-ol and
octadecan-1-ol. Smaller quantities of these should be used and the mixture stirred during
cooling. If a cooling curve particularly for naphthalene is required use a loose plug of cotton
wool in the mouth of the tube. Naphthalene should not be heated in an open laboratory.
Phenyl benzoate provides a suitable alternatives for recrystallisation experiments.
The nitration of naphthalene is not a suitable experiment for schools.
(FC)
© ASE 2003 (adapted from Safety in Science Education, 1996 (HMSO) and Topics in Safety, 1988 & 1982
Solutions do not seem to present the same problems as some solids but may cause allergic
reactions.
When nickel plating restrict current to 10 mA cm-2 and carry out in a very well ventilated
room or preferably in a fume cupboard.
For abbreviations see Introduction
Nickel(II) carbonate, solid
Xn, Xi, Carc 3(inhal), Sen
Y12
N13
(S5)
Nickel(II) chloride
T, Carc 3(inhal), Sen
Y12
N13
S6
Nickel(II) nitrate
O, T, N, Carc 3, Sen
(Y9)
(N10)
(S4)
Nickel(II) oxide
T, Carc 1(inhal), Sen
Not generally recommended
Xn, N, Carc 3(inhal), Sen
N, Carc 3(inhal), Sen
Y12
Y9
Xn
F-, Xn
Teacher/Technician
(Y9)
(N10)
S5
Nital (cleaning mixture)
F
(Y12)
(N13)
(S6)
Nitrates(III) (nitrites)
solid
O, T, N
Y12
N13
S5
T
Xn
Y9
N10
S5
O, Xi
may have additional
hazards depending on the
cation
Y9
N10
S2
For sources of metal ions in solution
Y11
N12
S5
For heating, testing for nitrates (Devardas Alloy and Brown Ring), etc. The action of heat
generally produces nitrogen dioxide which is toxic. If, in the thermal decomposition of a
nitrate, oxygen is being tested for care needs to be taken that the splint does not drop into the
molten mass.
Nitrates should not be mixed with reducing agents and heated.
Nickel(II) sulfate.
solid & solutions >10%
solution
10 to 25%
Ninhydrin
(> 0.4M)
solid
spray (in butan-1-ol)
solutions > 5%
1% to 5%
Nitrates(V) (nitrates)
(approx. 0.6M)
N13
N10
Substance is dusty; dispense carefully and avoid generating aeosols, eg if dissolving in dilute
acid, cover loosely with watch glass or carry out in fume cupboard.
Crystalline and unlikely to be inhaled unless aerosol created by electrolysis or evolution of a
gas from the same solution.
This material is carcinogenic by inhalation and is often found in use in Art departments. Its
use is not recommended in schools. It could be adventitiously formed by heating carbonates,
nitrates or hydroxides.
S6
(S2)
FC
© ASE 2003 (adapted from Safety in Science Education, 1996 (HMSO) and Topics in Safety, 1988 & 1982
The material is generally supplied as a solution in butan-1-ol and ignition sources must not
be nearby. Set up in the fume cupboard a disposable spray booth made from a small
cardboard box with one side cut away; this prevents the cupboard from being contaminated.
Wear gloves.
There are many published recipes for this reagent. Do not use more than 2 cm3 of conc.
nitric acid for 98 cm3 ethanol. Mixtures containing larger amounts of nitric acid are
unstable.
Ammonium nitrite should not be heated; nitrogen can be prepared by the teacher heating on
a small scale a dilute solution of ammonium chloride and sodium nitrite. Nitrites react with
acid to eventually produce toxic nitrogen dioxide. There is potential for the confusion of
nitrites with nitrates: they are best stored separately.
For abbreviations see Introduction
Nitric acid
fuming (100%)
O, C
Teacher/Technician
FC
FC
concentrated (70%),
(16M)
O, C
Teacher/Technician
concentrated (70%),
(16M)
O, C
(Y12)
(N13)
(S5)
(FC)
concentrated (70%),
(16M)
(1M)
O, C
C
(Y12)
Y9
(N13)
N10
(S6)
S2
(FC)
(> 0.8M)
C
Nitric oxide
Nitroanilines
Nitrobenzene
T, N
4-nitrobiphenyl
T, N, Carc 2
Nitrocellulose
E
Y12
N13
S6
see
Nitrogen monoxide
see
Nitrophenylamines
(FC)
Readily absorbed via skin and by inhalation. Small quantities may be used in a well
ventilated laboratory. There is a danger of cumulative effects if this compound is handled
often. Small quantities used once or twice in advanced courses by senior students should not
present a danger. Gloves should be worn.
Banned
Banned by COSHH.
Not generally recommended
Nitroaniline
Nitrogen dioxide
T+
- cylinders
- prepared as needed
T+
Teacher/Technician
Y12
N13
S6
- test tube quantities
T+
(Y9)
(N10)
If nitrogen dioxide is expected in anything other than the very smallest quantities , a fume
cupboard should be used. Nitric acid reacts violently with organic substances, ethanoic acid,
ethanol, propanone, aluminium, lithium, magnesium and the alkali metals and thiocyanates
and thiosulfates. Nitric acid should not be used to clean crucibles that have been used to
heat magnesium. The use of mixtures of the acid and alcohol to clean glassware is not safe
for schools use. If 'Aqua Regia' is used to dissolve metal alloys, the mixture must be made
up using fresh cooled acids and not stored. The production of brown colouration in the
liquid is a sign that decomposition has started to occur and the mixture should be disposed of
by pouring into very large volumes of water.
Preparation of acid from nitrate and conc sulfuric acid.
Ostwald process - use small scale apparatus; see Ammonia in HazChemMan CD2 (SSERC).
Preparation and use of Aqua Regia.
Reactions with copper, on small scale. If nitrogen dioxide is expected in more than small
amounts, use a fume cupboard.
Oxidation and nitration of organic compounds.
Comparison of dilute acids and preparation of nitrates. Use 0.5M or even 0.1M where
possible.
Not suitable for use in schools.
see
Nitrophenylamine
FC
Very toxic by inhalation and severe irritant to respiratory system, eyes and skin. Delayed
symptoms can follow an exposure and if the gas is inhaled it should be treated as a matter for
concern.
Hydrogen ignites spontaneously in air if nitrogen dioxide is present. The reactions of the gas
with alcohol, hydrocarbons and halogenoalkanes are vigorous and dangerous. The gas reacts
with amines to form carcinogenic N-nitrosamines.
Not suitable for schools.
Small quantities may be prepared in a well ventilated laboratory by younger students under
supervision. Pupils should be taught how to smell gases safely (See Safeguards 4.3) before
attempting to smell this gas.
Small quantities of metal nitrates may be heated.
(FC)
(S4)
© ASE 2003 (adapted from Safety in Science Education, 1996 (HMSO) and Topics in Safety, 1988 & 1982
For abbreviations see Introduction
Nitrogen monoxide
(Nitric oxide)
T+
As with nitrogen dioxide it is very toxic by inhalation and severe irritant to respiratory
system, eyes and skin. Again delayed symptoms can follow an exposure and if the gas is
inhaled it should be treated as a matter for concern.
Not recommended for use in schools.
Small quantities may be prepared in a well ventilated laboratory. The gas reacts violently
with methanol. The reaction with carbon disulfide is not recommended as explosions have
occurred.
- cylinders
- prepared as needed
T+
T+
Not generally recommended
Y12
N13
S6
(FC)
- test tube quantities
T+
(Y9)
(FC)
Nitrogen triiodide
E
Not generally recommended
Preparation not recommended in schools.
Nitromethylbenzenes
(Nitrotoluenes)
T
Not generally recommended
Not recommended for use in schools.
2-nitronaphthalenes
T, N, Carc 2
Nitrophenols
Xn
(Y12)
Nitrophenylamines
(Nitroanilines)
T
Teacher/Technician
Xi
Xi
Teacher/Technician
Y9
N10
S2
(N10)
S4
Banned
N13
Known carcinogen. Effectively banned in schools by government education departments
(AMs in England and Wales, SEED Circulars in Scotland and DENI Guidance in N.Ireland)
S6
These compounds should not be made on a preparative scale.
These compounds should not be made on a preparative scale.
4[(4-nitrophenyl)azo]benzene-1,3-diol
(Magneson I) and
4[(4-nitrophenyl) azo] naphthalen-1-ol
(Magneson II) .
solids
solution (0.5 % in 0.25M sodium
hydroxide)
Some recipes use 1M sodium hydroxide as the solvent. These solutions are corrosive and
best avoided for use by younger students.
Nitrosamines, in general
T & many are potent
carcinogens
Banned
Known carcinogens. Effectively banned in schools by government education departments
(AM70 in England and Wales, SEED Circular 8/95 in Scotland and DENI Guidance in
N.Ireland). Avoid having nitrites or nitrogen dioxide in the presence of amines, especially
secondary amines, as potent carcinogenic N-nitrosamines will form.
Nitrosonaphthalenes
T
Banned
Effectively banned in schools by government education departments (AM70 in England and
Wales, SEED Circular 8/95 in Scotland and DENI Guidance in N.Ireland.)
Nitrosophenols, 2- and 3- isomers
T
Banned
Known carcinogens. Effectively banned in schools by government education departments
(AM70 in England and Wales, SEED Circular 8/95 in Scotland and DENI Guidance in
N.Ireland). These could be adventitiously formed during the nitration of phenol. Nitration
should not be carried out with the usual nitrating mixture but with a solution of sodium
nitrate and sulfuric acid in an ice bath. The products of the reaction should only be handled
with gloves on and the reaction tube wrapped in paper and discarded at the end of the
experiment. Do not attempt to wash out the tubes.
4-nitrosophenol
Xn, N
(Y12)
(N13)
(S6)
Unlike other nitrosophenols this material is not thought to be carcinogenic.
Nitrotoluenes
see
Nitromethylbenzenes
Nitrous oxide
see
Dinitrogen oxide
© ASE 2003 (adapted from Safety in Science Education, 1996 (HMSO) and Topics in Safety, 1988 & 1982
For abbreviations see Introduction
Octane
F, Xn, N
Y9
N10
S5
(FC)
Oct-1-ene
F, Xn
Y12
N13
S5
(FC)
Oleum'
C
Not generally recommended
T+
NR
Orthophosphoric acid
Not recommended for use in schools
see
Osmic acid
NR
(S6)
Oxalic acid & oxalates
Phosphoric(V) acid
Only use with strict supervision.
see
Ethanedioic acid & ethanedioates
O
Oxygen
- cylinder
Teacher/Technician
- prepared as needed large scale
small scale
'Oxygen mixture'
( Potassium chlorate (V) plus
manganese(IV) oxide)
Y12
N13
S6
Y7
N8
S1
See Handbook (CLEAPSS) or HazChemMan CD 2 (SSERC) for advice on handling
cylinders.
The preparation of oxygen from potassium chlorate(V) should be avoided. The use of
hydrogen peroxide and manganese(IV) oxide is much safer.
Small scale preparation from manganese(IV) oxide and 5 vol hydrogen peroxide and tests on
the gas.
Not generally recommended
Not recommended for use in schools. Oxygen is best prepared by the action of
manganese(IV) oxide on hydrogen peroxide solution.
'Paraffin'
(Kerosene)
F-, Xn
(Y9)
(N10)
S2
This is the 'paraffin that is used as a fuel. Very flammable only as aerosol or if heated.
Paraffin, liquid
("Liquid paraffin")
Low hazard
Y9
N10
S3
Used in cracking hydrocarbon experiments.
Paraldehyde
see
Ethanal Trimer
Paraquat
T+, N
Liquid not suitable for use in schools; material supplied for professional agricultural use is
particularly dangerous. ( Some pesticides may still contain paraquat, but in formulations
which are very dilute with the chemical incorporated into soluble granules rather than as
liquid.)
Pentane
F+, Xn, N
Y8
N9
S5
(FC)
Pentan-1-ol and pentan-2-ol
(Amyl alcohols)
F-, Xn
Y11
N12
S5
(FC)
Pentan-2-one
(Propyl methyl ketone)
F, Xn
Y11
N12
S5
(FC)
Pentan-3-one
(Diethyl ketone)
F, Xi
Y11
N12
S5
(FC)
Pentyl ethanoate
(Amyl acetate)
F-
Y9
N10
S5
(FC)
Very small quantity may be used by S1.
perchlorates
see
Chlorates(VII)
Perchloric acid
see
Chloric(VII) acid
© ASE 2003 (adapted from Safety in Science Education, 1996 (HMSO) and Topics in Safety, 1988 & 1982
Use on very small scale in well ventilated laboratory or in fume cupboard. Ensure absence
of ignition sources.
For abbreviations see Introduction
Peroxides, inorganic
generally
but barium peroxide
are
Peroxodisulfates(VI)
(persulphates)
O, C
O, Xn
Y12
N13
S5
Fire or explosion hazard if mixed with metals, non-metals, cloth, paper or wood.
O, Xn, Sen
(Y12)
(N13)
S6
Fire or explosion hazard if mixed with metals, non-metals, cloth, paper or wood.
Decomposes slowly and pressure may build up in container.
Petroleum spirits
(Petroleum ether fractions)
The 60/80oC fraction contains quite an amount of hexane; if using this fraction take extra
care to avoid skin contact with liquid or inhalation of vapour.
Very small quantities may be used in a well ventilated laboratory provided no sources of
ignition are present.
Small quantities may be used in a well ventilated laboratory provided no sources of ignition
are present.
Small quantities may be used in a well ventilated laboratory provided no sources of ignition
are present.
bp below 30/40oC
F+, Xn, N
Y12
N13
S6
(FC)
bp below 80oC
F, Xn, N
Y12
N13
S6
(FC)
bp above 80oC
F, Xn, N
Y9
N10
S2
(FC)
T
T
(Y12)
Y12
(N13)
(N13)
(S5)
S5
solution 1 to 5%
Xn
Y12
N13
S5
Phenolphthalein
solid
solution in ethanol
Xn
F
Teacher/Technician
Y7
N8
S3
Preparation of solution.
The main hazard is the high flammability of the ethanol.
(Y12)
Y12
Rapidly absorbed through the skin; wear nitrile gloves. Phenylamine reacts violently with
nitric acid and peroxides. See the sections on naphthalene-1- and -2 -ol for notes on the
preparation of azo dyes. When diazonium compounds are prepared it is important to check
that the reaction is complete by adding extra nitrite solution and testing a sample with
acidified KI solution.
Phenol solid
solution
> 5%
Phenylamine
(Aniline)
liquid & solutions
solutions
> 1%
0.2% to 1%
Phenylammonium salts
(Anilinium salts)
solid & solutions
> 1%
solutions 0.2% to 1%
T, N, Carc 3
Xn
(N13)
N13
(S6)
S6
T, N, Carc 3
(Y12)
(N13)
(S6)
Xn
Y12
N13
S6
Phenyl benzoate
Phenyl benzenecarboxylate
(Phenyl benzoate)
Xn
Y12
N13
Use sulfuric acid to prepare methanal / phenol polymers. Do not nitrate with a nitration
mixture, use a mixture of sodium nitrate and acid or 4M nitric acid alone.
Rubber gloves need to be worn if the solid is used as phenol is rapidly absorbed through the
skin and can cause burns if it comes in contact with the skin. Glycerol or
polyethyleneglycol (PEG) rubbed into the affected area can minimise or even prevent
blistering.
Very dilute solutions can be handled by younger students.
FC
(FC)
Being ionic solids these are much less volatile and hence easier to handle than liquid
phenylamine. Furthermore in many applications of phenylamine the first step is often the
conversion to the salt.
see
Phenyl benzenecarboxylate
S5
This material is an excellent substitute for benzene in nitration reactions.
Phenyl bromide
see
Bromobenzene
Phenyl chloride
see
Chlorobenzene
p-phenylene diamine
see
Benzene-1,4-diamine
© ASE 2003 (adapted from Safety in Science Education, 1996 (HMSO) and Topics in Safety, 1988 & 1982
For abbreviations see Introduction
Phenylethanone
(Acetophenone or methylphenyl ketone)
Xn
Y12
N13
S6
(FC)
Phenylethene
(Styrene)
F-, Xn
Y12
N13
S6
FC
Phenylhydrazine and salts
T
Y12
N13
S6
Phenyl 2-hydroxybenzenecarboxylate
(Phenyl salicylate) (Salol)
Low hazard
Y7
N8
S3
Phenylmethanol
(Benzyl alcohol)
Xn
Y12
N13
S6
An alkanol of low volatility and flammability.
Phenyl thiocarbamide (PTC), solid
(Phenylthiourea) (PTU)
T+
Teacher/Technician
S3
Preparation of strips: For testing the ability to taste this substance, use only a paper strip.
Each strip should contain no more than 0.1mg. Stock solutions and solid should be locked
away and never tasted. Prepare strips by dipping in a solution of no more than 0.1g per litre.
Taste no more than 2 strips.
- prepared paper strips
(Y9)
N10
Phoroglucinol
Avoid skin contact.
see
Phosphides, metal
F, T+, N
Not generally recommended
Phosphine
T+
Teacher/Technician
Phosphoric(V) acid . Liquid
solution > 25%
( >2.8M)
10 to 25%
(1M to 2.5M)
C
C
Xi
Y12
Y9
Y9
N13
N10
N10
S6
S5
S4
Phosphorus (Red)
F, N
Y12
N13
TT
Phosphorus (White)
F, T+ C, N
Teacher/Technician
Phosphorus(V) bromide
(Phosphorus pentabromide)
C
(Y12)
(N13)
S6
The polymerisation should be initiated with di(dodecanoyl) peroxide. The material has a
stabiliser added to inhibit autopolymerisation. The stabiliser needs to be removed by
shaking with dilute sodium hydroxide solution before the polymerisation is attempted. Use
all of the treated phenylethen - do not store.
Benzene-1,3,5-triol
Not recommended for use in schools.
FC
The preparation of the gas must be carried out in a fume cupboard. Impurities in the gas
render it spontaneously flammable in air. The pure gas will only inflame if it is very dry and
the air is cold.
(FC)
Small quantities may be used in a well ventilated laboratory. Forms explosive mixtures with
chlorates and metal oxides. All spatulas etc. that have been used to handle red phosphorus
need to be washed with water, the washings filtered and the filter paper burnt in a fume
cupboard. Alternatively simply roast the spatula in a fume cupboard.
FC
Liable to ignite spontaneously; always handle with tongs and cut under water in a strong
container such as a mortar. For combustion reactions ignite with a hot glass rod. White
phosphorus ignites on contact with iodine but explodes with liquid bromine.
It is recommended that red phosphorus be substituted for very toxic white phosphorus where
possible. Though slower to ignite the red allotrope is satisfactory for most applications.
In the reaction with chlorine no heat is needed and leaving the solid wet allows time for the
maniplulation of the apparatus before the phosphorus ignites.
(FC)
Vigorous reaction with water.
© ASE 2003 (adapted from Safety in Science Education, 1996 (HMSO) and Topics in Safety, 1988 & 1982
For abbreviations see Introduction
Phosphorus(V) chloride
(Phosphorus pentachloride)
T+
(Y12)
(N13)
(S5)
Phosphorus(V) oxide
(Phosphorus pentoxide)
C
(Y12)
(N13)
(S5)
Phosphorus oxychloride,
(phosphoryl chloride)
Phosphorus(III) bromide
(Phosphorus tribromide)
(FC)
Violent reaction with water, sodium and potassium. Add only a very small amount to water
or to an alkanol in a well ventilated laboratory.
For the the preparation of acid chlorides always lead any gases produced down into a sink
with the tap running and distil the mixture from a water bath, not with direct heat.
If a crust has formed on the solid it should be removed and treated as a solid acid for
disposal (unreacted oxide will be sticking to the solid). The oxide reacts violently with
water and iodides. Sodium and potassium metals ignite on contact with phosphorus(V)
oxide.
The oxide must not be used for dehydration of methanoic acid as large volumes of carbon
monoxide are produced.
Further information is available on alternative drying agents in the Hazardous Chemicals
Manual CD2 (SSERC) or the Handbook (CLEAPSS).
see
Phosphorus trichloride oxide
C
(Y12)
(N13)
(S6)
FC
Vigorous reaction with water.
Phosphorus(III) chloride
(Phosphorus trichloride)
T+, C
(Y12)
(N13)
(S6)
FC
Violent reaction with water, sodium and potassium. Add only a very small amount to water
or to an alkanol in a well ventilated laboratory.
For the the preparation of acid chlorides always lead any gases produced down into a sink
with the tap running and distil the mixture from a water bath not with direct heat.
Phosphorus trichloride oxide
(Phosphorus oxychloride, phosphoryl
chloride)
T, C
(Y12)
(N13)
S6
FC
Phthalic anhydride
Picric acid
Potassium
F, C
Benzene-1,2-dicarboxylic anhydride
see
2,4,6-trinitrophenol
Teacher/Technician
Y12
N13
Schools are advised not to keep large quantities of the metal and stocks must be checked on
a regular basis. Old stock of this metal that have started to go yellow due to the production
of super oxide may explode when cut. It should be destroyed by adding it a small piece at a
time to butan-1-ol, butan-2-ol or 2-methylbutan-2-ol.
Potassium should never be burnt in pure oxygen or chlorine. Potassium reacts explosively
with ice. Alloys of potassium with sodium should not be prepared as they spontaneously
inflame in air.
The fusion test with 1,1,1-trichloroethane and other halogenated hydrocarbons is dangerous
and should not be attempted. Alternatives are the Shoenig Oxygen flask method or
Middleton's Test.
S6
C
Not generally recommended
Potassium bromate(V)
T, O, Carc 2
Y12
N13
S6
Potassium carbonate
Xn
Y7
N8
S1
Potassium amide
(Potassamide)
see
Potassium bisulphate
Not recommended for use in schools.
see
© ASE 2003 (adapted from Safety in Science Education, 1996 (HMSO) and Topics in Safety, 1988 & 1982
Potassium hydrogensulfate
The toxicity is mainly via ingestion and handling dilute solutions presents negligible risk.
For abbreviations see Introduction
Potassium chlorate(V)
(chlorate)
O, Xn
Y12
Teacher/Technician
Avoid concentrated sulfuric acid as unstable chlorine dioxide will be formed which will give
rise to a serious risk of explosion.
Do not allow solutions to dry on wood, paper or clothing as these may ignite at a later time.
Thermal decomposition with and without trace of MnO2. Need for cleanliness. Do not
return unused chlorate(V) to jar and replace lid immediately to exclude dust.
This compound can react violently with reducing agents and should not be mixed with the
following:
Not generally recommended
ditto
ditto
ditto
ditto
ditto
(i) sulfur or sulfides
(ii) ammonium salts
(iii) phosphorus
(iv) 2,4,6- trinitrophenol (picric acid)
(v) fine metal powders such as aluminium and magnesium
(vi) 3,4,5- trihydroxybenzoic acid (gallic acid.)
ditto
(vii) fuels such as sugar and hydrocarbons.
Y12
Y12
Potassium chlorate(VII)
(perchlorate)
O, Xn
N13
N13
N13
S6
S6
S6
Use 0.05M solutions in redox reactions
Solutions of chlorates(V) produced, eg of potassium potassium or chlorate produced during
determination of solubility/ temperature curves should not be allowed to dry out. The solid
may be recovered by recrystallisation at the end of the measurement, but this should not be
used for heating experiments.
Not generally recommended
Not recommended for use in schools Need for cleanliness. Do not return unused
chlorate(V) to jar and replace lid immediately to exclude dust
Preparation of solutions.
Use of 0.05M solutions in test-tube redox reactions.
Do not allow solutions to dry on wood, paper or clothing as these may ignite at a later time.
This material is produced in the disproportionation reaction of potassium chlorate(V). If the
solid is crystallised out it should not be stored for use in other experiments.
Teacher/Technician
Y12
N13
S6
Potassium cyanide
solid
solution
> 7%
1 to 7%
0.1 to 1%
T+, N
T+, N
Not generally recommended
Teacher/Technician
Teacher/Technician
T, N
(Y12)
(N13)
(S6)
Xn
(Y12)
(N13)
(S6)
Not recommended for use in schools
FC
FC
© ASE 2003 (adapted from Safety in Science Education, 1996 (HMSO) and Topics in Safety, 1988 & 1982
In exceptional circumstances small amounts of dilute solutions can be used by experienced
teachers. Solutions of cyanides are sometimes used in advanced biological experiments or
as a masking agent in analytical work. It is safest if ready prepared solutions are bought in
as and when they are needed and used only by staff.
For abbreviations see Introduction
Potassium dichromate(VI)
Y12
solid & solutions >7%
(> 0.23M)
0.5% to 7%
(0.017 to 0.23M)
0.1% to 0.5%
(0.003 to 0.017M)
Insoluble solids
Potassium fluoride
solid
solutions, 3 to 25%
(0.5 to 4M)
Potassium hexacyanoferrates(II)
(ferrocyanide)
solid
solution
Potassium hexacyanoferrates(III)
(ferricyanide)
solid
solution
Potassium hydrogensulfate
(bisulphate)
solid
solution > 10%
(0.7M)
5% to 10%
(0.4 to 0.7M)
Potassium hydroxide
solid or melt
solutions > 25%
5 to 25%
2 to 5%
0.5 to 2%
Potassium iodate(V)
( > 5M)
( 1 to 5M)
(0.4 to 1M)
(0.1 to 0.4M)
T+, N, Carc 2(inhal), Sen
T, Carc 2(inhal), Sen
T, Carc 2(inhal)
T, Carc 2(inhal)
T
Xn
N13
S6
Y12
N13
S5
Y10
N11
S3
Y9
N10
S2
Not generally recommended
For preparations involving oxidation and titrations use manganate(VII) where possible. Use
on as small a scale as is reasonable. Avoid creating dust - this is easy owing to the large
crystals and avoid creating aerosols from solution, eg by vigorous gas evolution from
electrolysis, etc.
Oxidation of alcohols - ensure all the solid has dissolved and add the acidified dichromate
solution dropwise whilst mixing the contents of the flask thoroughly.
Use on as small a scale as possible.
Chromate precipates should not be isolated and dried in experiments.
Teacher/Technician
Y12
N13
S6
Forms explosive mixtures with nitrites and gives extremely toxic hydrogen cyanide if heated
with acids. Do not heat the solid.
Low hazard
Y12
Y9
N13
N10
S5
S2
Detection of iron(III) ions.
May explode with ammonia, forms explosive mixtures with nitrites and gives extremely
toxic hydrogen cyanide with acids. Do not heat the solid.
Low hazard
C
C
Xi
Y12
Y9
N13
N10
S5
S2
Y9
(Y7)
Y7
N10
(N8)
N8
S5
S2
S1
C
(Y12)
(N13)
(S6)
C
C
C
Xi
(Y12)
(Y12)
Y9
Y9
(N13)
(N13)
N10
N10
(S6)
(S6)
S3
S1
O, Xn
Y12
N13
S6
© ASE 2003 (adapted from Safety in Science Education, 1996 (HMSO) and Topics in Safety, 1988 & 1982
Detection of iron(II) and use in Ferroxyl indicator for corrosion testing.
Eye protection must be worn at all times when using this material no matter how dilute the
solution involved. Solutions > 1M cause severe burns. A corrosive aerosol is often given
off when solution is being prepared and good ventilation or a fume cupboard is needed..
Most reactions below Y9/S4 can be carried out with solutions weaker than 0.4M and below
S2/ Y8, solutions with lower concentrations (0.1M) are adequate for most work. Where
more concentrated solutions are required, eg for soap making then close supervision is
needed.
Reacts violently with aluminium, magnesium, carbon, sulfur, phosphorus or organic
materials. Potassium iodate has also been known to react violently with disulfate(VI)
(metabisulfite) if the dry solids are mixed and water then added. The reaction with
concentrated sulfuric acid can be carried out on a test tube scale, the residue being disposed
of by mixing with a large volume of water.
For abbreviations see Introduction
O, Xn, N
Potassium manganate(VII)
(permanganate)
Potassium nitrate(III)
(nitrite)
> 5%
1% to 5%
(Y7)
(N8)
(S1)
(FC)
Teacher/Technician
Heating solid is in a tube; as a very fine dust is produced; use a loose fitting plug of rocksil
or mineral wool or Superwool or carry out in a fume cupboard.
Large scale preparation of chlorine. Manganate(VII) forms an explosive mixture with
concentrated sulfuric acid or phosphoric acid and if the solid is being used to prepare
chlorine gas it is essential to double-check that the acid used in the reaction is hydrochloric
acid. The reaction is very vigorous and the hydrochloric acid must be added very slowly;
alternatively cover the solid iwith water. It is best not to use sulfuric acid for drying the gas.
Consider the use of Sodium chlorate(I) as alternative preparation.
Demonstration or reaction with propane-1,2,3-triol.
(Y12)
(N13)
(S6)
FC
Y11
Y12
N12
N13
S5
S6
Nitrates form explosive mixtures with aluminium, magnesium, sodium, potassium and other
metals plus ammonium salts, cyanides, sulfides, thiosulfates, and ethanoates. If, in the
thermal decomposition of a nitrate, oxygen is being tested for, care needs to be taken that the
splint does not drop into the molten mass. See also entry on Nitrates. Under supervision
with all students.
Y7 and S1 can use for solubility experiments and Y9 for heating.
Testing or reactions with concentrated sulfuric or phosphoric acids.
O, T, N
Y12
N13
S6
T
Xn
Y12
Y9
N13
N10
S6
S3
O
Potassium nitrate(V)
(nitrate)
solution
Being a powerful oxidising agent it can cause ignition of
(i) organic compounds - sugars, esters, aldehydes, esters, wood paper and
(ii) reducing agents - metals, sulfur, phosphorus. With some of these there is an induction
period, eg with propane-1,2, 3-triol. Ammonia and ammonium compounds may produce
explosive salts when mixed dry.
Acidified dilute hydrogen peroxide can be used to clean stains left by manganate(VII), but
concentrated hydrogen peroxide must not be used.
( > 0.6M)
(0.1 to 0.6M)
Potassium perchlorate
Potassium permanganate
Potassium peroxodisulfate(VI)
(persulphate)
O, Xn, Sen
Y12
N13
S6
Potassium phosphate (tribasic)
Xi
Y7
N8
S2
Potassium sulfide
C, N
Y11
N12
S5
React with acids to produce nitrogen monoxide which gives toxic nitrogen dioxide in air.
The solid is dangerous with ammonium salts, cyanides, and thiosulfates. It should not be
reacted with phenol which forms an explosive mixture.
see
Potassium chlorate(VII)
see
Potassium manganate(VII)
Can react violently with reducing agents, especially metal powders, organic compounds, and
can cause ignition of paper, cloth and wood. Store out of direct sunlight. Decomposes
slowly and pressure may build up in container - open carefully. Short shelf life.
(FC)
© ASE 2003 (adapted from Safety in Science Education, 1996 (HMSO) and Topics in Safety, 1988 & 1982
Produces very toxic, extremely flammable hydrogen sulfide with acids. Use 0.2M or weaker
solution for metal sulphide precipitation reactions.
For abbreviations see Introduction
Potassium thiocyanate
solid
solution
Xn
Low hazard
Procion Direct dyes
Sensitiser
solid
dilute solution for dyeing
Y12
Y9
N13
N10
Dangerous with concentrated sulfuric acid when the gas carbonyl sulfide is produced. Dilute
acid with boiling has the same effect but very slowly.
The very dilute solution provides very little hazard if used in the test for iron(III) but the
material should not be evaporated to dryness.
S4
S2
Two types of Direct dyes. Most are sensitisers by skin contact. HE types need a dyeing
temperature of 80ºC. MX types have the advantage of being fixed at the low temperature of
40ºC but two of the MX range are respiratory sensitisers (Orange MX-2R and Yellow MXR). With the latter two extra care is needed to avoid raising dust. Where possible purchase
"de-dusted" dyes.
Technicians should make solutions for reactions in a fume cupboard.
Solutions are safe for all levels.
Xi, Sen
Low hazard
Teacher/Technician
Y7
N8
S2
(FC)
Propanal
F, Xi
Y10
(FC)
Propane cylinder
F+
Not generally recommended
C
Xi
Y9
N10
S4
(FC)
Propan-1-ol and 2-ol
(n-propanol and isopropanol)
F, Xi
Y10
N11
S5
(FC)
Always use a water bath for heating. Propan-2-ol will form peroxides; test old samples for
presence of peroxides (see ethoxyethane) and if treated to remove peroxides, use
immediately and do not store.
In preparation of propanone by oxidation of propan-2-ol ensure the acidified
dichromare(VI) is added slowly with swirling or stirring between each addition.
Propanone
(Acetone)
F, Xi
(FC)
The reaction with halogenated hydrocarbons such as trichloromethane can be vigorous after
a long induction period (Ethyl ethanoate provides a safer alternative for measurement of
intermolecular forces). Nitric acid reacts violently with propanone. Do not use as a solvent
for oxidations by hydrogen peroxide or other peroxy compounds as propanone peroxides
will form. All heating must be done on a water bath.
Chromatography eluting agent or a example of a solvent using small scale.
Larger scale use as solvent and for properties of alkanones.
Propanoic acid
> 25%
10 to 25%
(4M)
(1.5 to 4M)
(Y7)
Y11
T, Carc 2, Sen
Propenamide
(Acrylamide)
N11
(N8)
N12
S5
Not recommended for use in schools except as source of piped burner supply.
(S1)
S5
Not generally recommended
Polymerisation of the monomer is not recommended in schools. For DNA electrophoresis
agarose works for most cases. If polyacrylamide is needed, purchase the gel in prepolymerised sheets or slabs.
Propionaldehyde
see
Propanal
Propionic acid
see
Propanoic acid
Propyl acetate
see
Propyl ethanoate
FC
Butylamine provideds a less volatile and less flammable alternative.
Suitable for test tube reactions. Dilute to 0.5M (approx. 4 cm3 made up to 100 cm3 )
Propylamine,
liquid
solution 5 to 10%
(ca.0.9 to 1.7M)
F, C
Y12
N13
S6
Xi
Y11
N12
S5
n-Propyl bromide
see
1-bromopropane
Iso-Propyl bromide
see
2-bromopropane
Propyl chlorides
see
Chloropropanes
© ASE 2003 (adapted from Safety in Science Education, 1996 (HMSO) and Topics in Safety, 1988 & 1982
For abbreviations see Introduction
Propylene dibromide
see
F, Xi
Propyl ethanoate
(acetate)
Y9
N10
S5
1,2-dibromopropane
(FC)
n-propyl iodide
see
1-iodopropane
Protactinium generator, preparation of
see
Uranium compounds
FC
No sources of ignition should be present.
see
Benzene-1,2,3-triol
see
Benzene-1,4-diol
see
Thorium compounds
F, Xn
Pyridine
Y12
N13
S6
Pyrogallol
Xn
Quinine
Teacher/Technician
Cold tea provides a good alternative for taste bud tests.
Quinol
Radon generator
Xi
Resazurin
Y9
N10
S2
Usually supplied in the form of tablets from which risk of exposure is negligible.
Resorcinol
see
Benzene-1,3-diol
Salicylic acid
see
2-hydroxybenzenecarboxylic acid
see
Phenyl 2-hydroxybenzenecarboxylate
Salol
Saponin
Xi
Y9
N10
S3
Screened methyl orange solution
F
Y7
N8
S4
Sebacoyl chloride
see
Selenium and compounds
T, N
Not generally recommended
Silicon tetrachloride
Xi
(Y12)
(N13)
(S6)
Silver nitrate, solid
C, N
Y12
N13
S6
C
Xi
(Y7)
Y9
(N8)
N10
S6
S2
Sodalime
(equivalent to a mixture of sodium and
calcium hydroxides)
C
(Y7)
(N8)
(S3)
Sodamide
C
Not generally recommended
solution
>10%
5 to 10%
( > 0.5M)
(0.3M to 0.5M)
Decanedioyl dichloride
An exhibition sample may be kept.
Smoking machine
© ASE 2003 (adapted from Safety in Science Education, 1996 (HMSO) and Topics in Safety, 1988 & 1982
Not recommended for use in schools.
For abbreviations see Introduction
Sodium
F, C
(Y12)
(N13)
(S6)
Reacts explosively with acids. Forms explosive mixtures with poly-halogenated
hydrocarbons. Violent reactions with bromine liquid, iodine, mercury and sulfur. The
addition of water to sodium (rather than the usual reaction of adding a small piece to a large
volume of water) is explosive due to the production of sodium oxide and sodium hydride and
is much too dangerous to be tried in schools.
In combustion reactions with oxygen and chlorine only small pieces should be used. In the
reaction with water first chill the water with a few ice cubes and only use a small piece of
sodium. The sodium must not be trapped in an attempt to collect the hydrogen unless an
apparatus specifically designed for the purpose is used. Alloys of sodium with potassium
spontaneously inflame in air.
For the sodium fusion test use very small amount (0.2g) of sodium with 0.1g of solid and a
safety screen or use Schoenig Oxygen Flask method.
Sodium amalgam
F, T, C, N
Y12
N13
(S6)
If mercury is used as the electrode in the electrolysis of sodium chloride solution the
amalgam produced must be totally reacted before the mercury is added to the stock of 'dirty'
mercury saved for purification. This can be achieved by covering the material with dilute
hydrochloric acid and leaving standing for several days (hydrogen is evolved, so carry out
in a well ventilated place). Alternatively add water and an iron nail.
If amalgam is prepared for preparative reductions, this must be done by the teacher or
technician.
Sodium azide
T+, N
Not generally recommended
Avoid use if at all possible. Small amounts of dilute solutions are sometimes used in
analytical procedures. Take care with disposal as it forms explosive azides with heavy
metals - drains may contain copper or even lead parts! Contact with acid liberates a very
toxic gas.
Sodium bisulfate
see
Sodium hydrogensulfate
Sodium bisuphfite
see
Sodium hydrogensulfate(IV)
see
Sodium tetrahydroborate
Sodium borohydride
Sodium carbonate
Sodium chlorate(I)
(hypochlorite)
solution
concentrated; >10% available chlorine
dilute,
0.5% to 10% available chlorine
Sodium chlorate(V)
(chlorate)
Xi
Y7
N8
S1
C
(Y9)
(N10)
S5
Xi
(Y7)
(N8)
(S1)
O, Xn
Y12
N13
S6
Teacher/Technician
© ASE 2003 (adapted from Safety in Science Education, 1996 (HMSO) and Topics in Safety, 1988 & 1982
Dangerous with conc. sulfuric acid. Forms explosive products with ammonium salts,
methanol, and amines. Gives chlorine with acids. If used to prepare chlorine 5M HCl
should be used. Sodium chlorate (I) is unstable in sunlight and should be stored in a
cupboard. As the solution gives off oxygen during storage it should be assumed that there
will be a pressure release on opening. The problem is worse in summer and accelerated by
some transition metal compounds.
Solutions of chlorine can be prepared on a small scale by adding a few cm3 of 1M
hydrochloric acid to a few cm3 diluted sodium chlorate(I) solution (The commercial 14%
solution should be diluted tenfold beforehand by the teacher or technician.)
Avoid concentrated sulfuric acid as unstable chlorine dioxide will be formed which will give
rise to a serious risk of explosion.
Do not allow solutions to dry on wood, paper or clothing as these may ignite at a later time.
Thermal decomposition with and without trace of MnO2 Need for cleanliness. Do not
return unused chlorate(V) to jar and replace lid immediately to exclude dust.
For abbreviations see Introduction
This salt can react violently with reducing agents and should not be mixed with the
following:
Not generally recommended
ditto
ditto
ditto
ditto
ditto
ditto
(i) sulfur or sulfides
(ii) ammonium salts
(iii) phosphorus
(iv) 2,4,6- trinitrophenol (picric acid)
(v) fine metal powders such as aluminium and magnesium
(vi) 3,4,5- trihydroxybenzoic acid (gallic acid.)
(vii) fuels such as sugar and hydrocarbons.
Y12
Y12
Use 0.05M solutions in redox reactions
Solutions of chlorates(V) produced, eg of potassium potassium or chlorate produced during
determination of solubility/ temperature curves should not be allowed to dry out. The solid
may be recovered by recrystallisation at the end of the measurement, but this should not be
used for heating experiments.
N13
N13
S6
S6
Sodium cobaltinitrite
see
Sodium chromate(VI)
- oxidation of alkanols
solid & solutions >7%
(> 0.23M)
0.5% to 7% (0.017 to 0.23M)
0.1% to 0.5% (0.003 to 0.017M)
Insoluble solids
Y12
T+, N, Carc 2(inhal), Sen
T, Carc 2(inhal), Sen
T, Carc 2(inhal)
T, Carc 2(inhal)
N13
S6
Y12
N13
S5
Y10
N11
S3
Y9
N10
S2
Not generally recommended
Sodium dichromate(VI)
- oxidation of alkanols
Y12
N13
S6
solid & solutions >7%
(> 0.23M)
0.5% to 7% (0.017 to 0.23M)
0.1% to 0.5% (0.003 to 0.017M)
Insoluble solids
T+, N, Carc 2(inhal), Sen
T, Carc 2(inhal), Sen
T, Carc 2(inhal)
T, Carc 2(inhal)
Y12
N13
S5
Y10
N11
S3
Y9
N10
S2
Not generally recommended
Sodium dithionite
Xn
(Y9)
(N10)
(S3)
© ASE 2003 (adapted from Safety in Science Education, 1996 (HMSO) and Topics in Safety, 1988 & 1982
Sodium hexanitrocobaltate(III)
For preparations involving oxidation and titrations use manganate(VII) where possible. Use
on as small a scale as is reasonable. Avoid creating dust - this is easy owing to the large
crystals and avoid creating aerosols from solution, eg by vigorous gas evolution from
electrolysis, etc.
Ensure all the solid has dissolved and add the acidified dichromate solution dropwise whilst
mixing the contents of the flask thoroughly.
Use on as small a scale as possible.
Chromate precipates should not be isolated and dried in experiments.
For preparations involving oxidation and titrations use manganate(VII) where possible. Use
on as small a scale as is reasonable. Avoid creating dust - this is easy owing to the large
crystals and avoid creating aerosols from solution, eg by vigorous gas evolution from
electrolysis, etc.
Ensure all the solid has dissolved and add the acidified dichromate solution dropwise whilst
mixing the contents of the flask thoroughly.
Use on as small a scale as possible.
Chromate precipates should not be isolated and dried in experiments.
Supply the material in solution for class use. Can cause fire if added to a small amount of
water. Weigh out in dry beaker. Sulfur dioxide may be evolved.
For abbreviations see Introduction
Xn
Y9
N10
S3
( > 0.4M)
Xn
Xn
Y12
Y9
N13
N10
S6
S5
(0.5 to 4M)
T
Xn
Teacher/Technician
Y12
N13
S6
Sodium hexanitrocobaltate(III)
(Sodium cobaltinitrite)
O, Xi
Y12
N13
S6
Sodium hydride
F
TT
TT
(S6)
Xi
Xi
(Y9)
(Y7)
Y7
(N10)
(N8)
N8
S3
S2
S1
Sodium dodecyl sulfate
(lauryl sulphate)
Sodium ethanedioate
(oxalate)
solid
solution
Sodium fluoride
solid
solutions 3 to 25%
Sodium hydrogensulfate
(bisulphate)
solid
solution 5 to 10 %
< 5%
(0.5 to 1M)
(< 0.5M)
Sodium hydrogensulfate(IV), solid
(hydrogensulphite or bisulphite)
solution
> 5%
Sodium hydroxide
solid or melt
solutions
> 25%
5 to 25%
2 to 5%
0.5 to 2%
( > 5M)
( 1 to 5M)
(0.5 to 1M)
(0.1 to 0.5M)
Xn
Reacts violently with water to give off hydrogen. Can ignite in moist air.
(FC)
Xn
(Y10)
(Y7)
((N11)
(N8)
(S4)
(S3)
C
(Y12)
(N13)
(S6)
C
C
C
Xi
(Y12)
(Y12)
Y9
Y7
(N13)
(N13)
N10
N8
(S6)
(S6)
S3
(S1)
Sulfur dioxide is readily evolved with dilute acids.
Use in test tube redox work.
As very dilute solution of sulfur dioxide.
Eye protection must be worn at all times when using this material no matter how dilute the
solution involved. Solutions > 1M cause severe burns. A corrosive aerosol is often given
off when solution is being prepared and good ventilation or a fume cupboard is needed.
Most reactions below Y9 or S4 can be carried out with solutions weaker than 0.4M. Below
S2/ Y8 levels 0.1M solutions are adequate for most work. Where more concentrated
solutions are required, eg for soap making, then close supervision is needed.
Sodium hypochlorite
see
Sodium chlorate(I)
Sodium lauryl sulphate
Sodium polytrioxovanadate(V)
(metavanadate)
solution > 5%
( > 0.4M)
0.5 to 5%
(0.04 to 0.4M)
see
Sodium dodecyl sulfate
Ammonium metavanadate provides a cheaper alternative for investigating the several
oxidation states of vanadium.
T, N
Y12
N13
S6
T
Xn
© ASE 2003 (adapted from Safety in Science Education, 1996 (HMSO) and Topics in Safety, 1988 & 1982
For abbreviations see Introduction
O
Sodium nitrate(V)
(nitrate)
Sodium nitrate(III)
(nitrite)
solution
> 5%
1% to 5%
( > 0.7M)
(0.14 to 0.7M)
Y11
Y12
N12
N13
S5
S6
O, T, N
Y12
N13
S6
T
Xn
Y12
Y9
N13
N10
S6
S3
Nitrates form explosive mixtures with aluminium, magnesium, sodium, potassium and other
metals plus ammonium salts, cyanides, sulfides, thiosulfates, and ethanoates.
If, in the thermal decomposition of a nitrate, oxygen is being tested for, care needs to be
taken that the splint does not drop into the molten mass. See also entry on Nitrates. All
students need to be supervised
Y7 and S1 can use for solubility experiments and Y9 for heating.
Testing or reactions with conc sulfuric or phosphoric acids.
Reacts with acids to produce nitrogen monoxide which gives toxic nitrogen dioxide in air.
The solid is dangerous with ammonium salts, cyanides, and thiosulfates. It should not be
reacted with phenol which forms an explosive mixture.
Sodium nitroprusside
see
Sodium pentacyanonitrosylferrate(II)
Sodium oxalate
see
Sodium ethanedioate
Sodium pentacyanonitrosylferrate(II)
(nitroprusside)
solution > 25%
( > 0.84M)
3 to 25%
(0.1 to 0.84M)
T
Sodium peroxide
Sodium sulfide
solid
solution
Sodium tetrahydroborate
(borohydride)
(Y12)
(N13)
S6
Toxic by inhalation and ingestion. Do not decompose by heat.
O, C
(Y12)
(N13)
(S5)
Combustible materials may ignite spontaneously especially if damp. The reactions with
ethanoic acid and ethanoic anhydride are explosive. It forms an explosive mixture with
tin(II) chloride. Reacts with water to give sodium hydroxide.
C, N
Xi
Y12
N13
S6
F, T
Teacher/Technician
T
Xn
FC
Reacts with acids to give toxic hydrogen sulfide.
This can be used in methanol or even in cold water for reduction of alkanones and alkanals
whereas the lithium aluminium hydride can ignite even in moist air and needs extremely dry
ethoxyethane.
Stannous salts
see
Tin(II) salts
Stannic compounds
see
Tin(IV) compounds
Strontium
F, C
Teacher/Technician
Handle with care.
Styrene
Sulphanilic acid
Sulfides of heavy metals
(Y9)
(N10)
(S2)
see
Phenylethene
see
4-aminobenzenesulfonic acid
(FC)
Use a fume cupboard if any reactions are to be investigated involving the use of acid as toxic
hydrogen sulfide is produced or if "simulated" or real sulfide ores are to be roasted (sulfur
dioxide evolved). If choosing ores from the "field", choose carefully to ensure no metal
arsenides are also present.
© ASE 2003 (adapted from Safety in Science Education, 1996 (HMSO) and Topics in Safety, 1988 & 1982
For abbreviations see Introduction
F
Sulfur
Y7
N8
(S2)
(Y9)
(N10)
(S2)
(FC)
Sulfur burns to give the toxic sulfur dioxide gas. All reactions that involve the possibility of
sulfur igniting should preferably be carried out in a fume cupboard. When heating sulfur
alone or with iron in a test-tube in an open laboratory, use a loose plug of mineral wool or
Superwool to minimise the escape of the sulfur vapour and its ignition. See entry on Sulfur
dioxide.
The reaction of sulfur with oxidising agents such as chlorates must not be carried out in
schools.
The reactions with magnesium, aluminium or more reactive metals are too violent and
should not be carried out.
The reactions with copper and iron may be carried out provided safety screens are used.
The reaction with zinc powder (avoid fine zinc dust) is possible provided small amounts are
used and the mixture is not restricted in any way and safety screens are used.
Sulfur chlorides
T, C, N
(Y12)
(N13)
(S6)
FC
Reacts with water producing a range of sulfur compounds. The use of a fume cupboard is
essential and supervision needded if students use the material.
Sulfur dichloride dioxide
(Sulfuryl chloride)
C
(Y12)
(N13)
(S6)
FC
Reacts slowly with cold water and rapidly with hot water to give toxic and corrosive fumes
of sulfuric and hydrochloric acids.
Sulfur dichloride oxide
(Thionyl chloride)
C
(Y12)
(N13)
(S6)
FC
Irritating to respiratory system. Wear gloves. Considered to be more toxic than sulfur
dioxide.
Sulfur dioxide
- canister
T
(Y12)
(N13)
(S6)
FC
- preparation, large scale
- test tube preparation
- reaction rates with thiosulfate
T
T
T
Y12
(Y9)
Y10
N13
(N10)
N11
S6
S3
S4
FC
(FC)
- use of aqueous solution
Xi (if 0.5 to 5%)
C (if > 5%)
Y10
N11
S4
(FC)
Sulfuric acid
concentrated, (98%)
(18M)
( > 1.5 M)
( 0.5 to 1.5 M)
C
(Y12)
(N13)
(S6)
C
Xi
(Y9)
(Y7)
(N10)
(N8)
(S5)
(S2)
© ASE 2003 (adapted from Safety in Science Education, 1996 (HMSO) and Topics in Safety, 1988 & 1982
Many students may be susceptible to asthma attacks which can be brought on by small
quantities of the gas. A warning should be issued before the experiment whenever there is a
possibility of the gas being evolved in a reaction.
The valves of canisters of sulfur dioxide should be checked and replaced regularly as they
are prone to corrode. The valve should not be screwed down too tight as this eventually
produces a hole too large for the valve to seal. The older aluminium canisters can no longer
be purchased. Rubber tubing that has been used for reactions involving the gas should be
discarded after use.
Immediately a run is finished, greatly dilute with water and then wash to waste to minimise
the amount of sulfur dioxide escaping. When investigating the effect of temperature, do not
heat solutions above 30 or 40ºC, but extend the range downwards with ice-chilled water.
Supply a solution of the gas made by teacher or technician for use by pupils.
Alternatively pupils prepare in test tube by adding a few drops of 1M sulfuric acid to a pinch
of sodium sulfate(IV) in water.
The reactions with chlorates(V) and manganate(VII) produce spontaneously explosive
products. The reaction with sugar can produce large volumes of carbon monoxide and the
product needs to be washed thoroughly before it is touched. The reaction with water is very
exothermic and solutions must be made by the addition of the acid to the water with mixing.
The Charle's Law apparatus (glass U-tube with graduated limb) is more accurate than the use
of a mercury bead trapped in a short length of sealed capillary tube, though the latter is safer.
For abbreviations see Introduction
Sulfuryl chloride
see
Sulfur dichloride dioxide
Tellurium metal
T
Not generally recommended
Keep as exhibition sample only.
Tellurium compounds
T
Not generally recommended
Not suitable for use in schools.
Tetrachloromethane
(Carbon tetrachloride)
T, N
(Y12)
Thallium metal
T+
Not generally recommended
Not suitable for use in schools.
Thallium salts
T+, N
Not generally recommended
Not suitable for use in schools.
Thiocarbamide
(Thiourea)
Xn, N, Carc 3
Y12
N13
S6
Xn
Y12
N13
S5
Low hazard
Y9
N10
S2
T, Radioactive
TT
TT
XX
(Y12)
(N13)
XX
C
Xi
Y10
N13
S5
Tin(IV) chloride
(Stannic chloride)
C
Y12
N13
S6
Titanium(IV) chloride
(Titanium tetrachloride)
C
Teacher/Technician
C
Y12
Thiocyanates
solid
solution
(N13)
(S6)
Thionyl chloride
Thorium compounds
Tin(II) chloride- 2- water
o-tolidine
Tollen's Reagent
N13
It is difficult to obtain from suppliers on account of its ozone depleting properties. It might
be possible to obtain it in order to show its unique properties, ie comparison of hydrolysis of
halides across the periodic table or down Group IV. Do not use as solvent or in applications
where it is lost by evaporation. Use only in an efficient fume cupboard.
Reactions with magnesium and aluminium are violent.
Dangerous with concentrated sulfuric acid when the gas carbonyl sulfide is produced. Dilute
acid with boiling has the same effect but very slowly. Explosive with several oxidising
agents.
The very dilute solution provides very little hazard if used in the test for iron(III) but the
material should not be evaporated to dryness.
Cobalt thiocyanate paper sometimes recommended in place of cobalt chloride.paper.
see
- Radon Generator
Tin(II) chloride (Stannous chloride)
FC
Sulfur dichloride oxide
Schools in Scotland are not permitted to hold thorium salts, but are recommended to instead
use the protactinium generator for half life measurement.
Schools in England, Wales and Northern Ireland can apply to use thorium compounds as
chemicals; however these count as open sources and the Ionising Radiation Regulations
1999 (IRR) will require a thorough risk assessment to be made and the compounds used only
in designated "Controlled Areas". In schools it will be very difficult if not impossible to
meet these requirements.
Maintained schools in England and Wales need approval from the DfES or WAG; the higher
category B is needed for thorium compounds other than in radon generators.
Can form explosive mixture with oxidising agents such as nitrates and peroxides.
FC
Reacts with moist air and water to give fumes of hydrogen chloride. Wear nitrile gloves.
Explosive mixture with turpentine.
FC
Violent reaction with water producing hydrogen chloride. Bottles of this material should be
opened with caution, covering with a dry cloth as HCl gas may escape under pressure.
see
3,3'-dimethylbiphenyl-4,4'-diamine
S5
© ASE 2003 (adapted from Safety in Science Education, 1996 (HMSO) and Topics in Safety, 1988 & 1982
Use a clean test tube. Make only as needed, heat on water bath just long enoughfor the
silver mirror to form; then discard the solution into a large volume of water and wash the
tube out with dilute nitric acid. Do not store the solution and do not add excess solution or
product of reaction to silver residues bottles.
For abbreviations see Introduction
Toluene
see
Methylbenzene
Existing stocks should only be used in ways which entail minimal evaporation. Its
manufacture has been phased out as it is an ozone depleter. This liquid had been used as a
safer solvent in applications where tetrachloromethane or trichloromethane were used.
It should be treated with care. The reactions with metals such as magnesium, aluminium,
sodium are violent or explosive.
1,1,1-trichloroethane
(Methylchloroform)
Xn, N
(Y12)
(N13)
S6
(FC)
2,2,2-trichloroethanediol
(Chloral hydrate)
T
Y12
N13
S6
FC
Trichloroethanoic acid
(Trichloroacetic acid)
solutions > 5%
( > 0.3M)
1 to 5%
(0.06M to 0.3M)
C, N
(Y12)
(N13)
(S6)
Do not heat, decomposition can produce a toxic gas.
C
Xi
(Y12)
(Y12)
(N13)
(N13)
(S6)
(S6)
Do not store solutions less than 30% for longer than necessary as such solutions are
hydrolysed to give trichloromethane, hydrogen chloride, carbon dioxide and carbon
monoxide. This can build up a high pressure in a stoppered bottle.
Trichlorethene
(Trichloroethylene)
T, Carc 2
(Y12)
(N13)
(S5)
FC
All handling where some vapour may escape must be done in a fume cupboard. This liquid
has been advocated as an alternative solvent for 1,1,1-trichloroethane and also for
tetrachloromethane or trichloromethane. However it should be treated with care.
The reactions with metals such as magnesium, aluminium, sodium are violent or explosive.
Vigorous reaction with alkalis.
Where possible substitute with cyclohexane, butyl ethanoate, Volasil, Lotoxane, etc.
Trichloromethane
(Chloroform)
Xn, Carc 3
Y12
N13
S5
FC
This material should only be used in an efficient fume cupboard and where there is no
suitable alternative available and never as a solvent. The reactions with aluminium and
magnesium are violent and those with sodium, potassium and lithium explosive. Alkalis in
the presence of alcohols or ketones show violent reactions. Trichloromethane should never
be heated to a high temperature in air as thermal decomposition can cause the production of
the very toxic carbonyl chloride (Phosgene).
The interaction with propanone to show intermolecular forces may become violent a long
time after mixing if traces of base are present. Ethyl ethanoate can be used in place of the
propanone.
Find alternatives where possible, eg
- for extraction of caffeine dichloromethane is a suitable, but should be used in a fume
cupboard.
- as second solvent for 2-D paper chromatography of plastid pigments replace
trichloromethane/pet ether with ethoxyethane/pet ether.
3,4,5-trihydroxybenzene carboxylic acid
(Gallic acid, 3,4,5-trihydroxybenzoic acid)
Xi
Y12
N13
S6
Triiodomethane
(Iodoform)
Xn
Y12
N13
S5
(FC)
This is usually encountered in the "Iodoform Test" for activated methyl groups. Use drop
scale; propanone reacts quickly, but some other compounds require some heating. Use the
minimum to avoid excessive triiodomethane being driven off.
© ASE 2003 (adapted from Safety in Science Education, 1996 (HMSO) and Topics in Safety, 1988 & 1982
For abbreviations see Introduction
Trimethylamine
45% solution in water
(7M)
24% solution in water
(4M)
5 to 10%
(approx 1M to 2M)
F+, C
F+, C
F, C
Xi
(Y12)
(Y12)
Y12
Y12
(N13)
(N13)
N13
N13
(S6)
(S6)
S6
S6
FC
FC
FC
This material is explosive and if stocks of the material need to be kept in schools they must
be checked regularly to ensure the material is kept very damp.
2,4,6-trinitrophenol
(Picric acid)
solid
E, T
saturated solution (approx. 1%)
Turpentine
Teacher/Technician
(Y12)
(N13)
The material should only be used in solution. Reactions of this material with alkali and
chlorates should not be tried.
(S6)
Xn, F-, N
Teacher/Technician
Y12
N13
S6
T+
NR
T+, N
Teacher/Technician
- Protactinium generator, preparation of
solution
Use of protactinium generator
T+, C, N
Teacher/Technician
(Y12)
(N13)
(S6)
Vanadium(V) oxide
(Vanadium pentoxide)
T, N
Y12
N13
S6
T, N
T
Y12
(Y9)
N13
(N10)
S6
S6
Wij's solution
(glacial ethanoic/chlorine/iodine)
F-, T, C
Y12
N13
S6
Xylene cyanol
Xi
F
Y12
Y9
N13
N10
S6
S2
Uranium
Uranium compounds,
Vanadium(V) salts
For most reactions a 0.5M solution or weaker is adequate to show properties.
solid
solid
solution
NR
XX
Zinc, powder
hydrogen preparation (test tube scale)
(large scale)
The metal is radioactive and very toxic, especially by inhalation. If used avoid any process
which generates dust. Its use in Scotland is banned; to use in the rest of the UK approval
needs to be sought from DfES, WAG or DENI. Not suitable for use in schools.
100 g of uranyl nitrate may be kept by schools authorised under Category C of the DES AM
1/92, SEED Circular 1166 and the DENI Guidance "Use of ionising radiations in educational
establishments (1986)" There are no discrete Welsh Directives in order to prepare
protactinium generators. Those working in Categories A and B may hold more.
For further details see Topic 19 in Topics, SSERC Explanatory Notes to accompany Circular
1166, SSERC Bulletins 158 & 199 and CLEAPSS Guide L93.
Vinyl chloride monomer
solid
solution (alcohol)
FC
(FC)
If being used to demonstrate the contact process ensure no dust escapes. If the "catalyst
chamber" (eg, combustion tube) is already filled with vanadium(V) oxide pellets, continue to
use it, but do not remove the pellets. Otherwise use platinised ceramic wool.
see
F
F
Being obtained from natural sources the composition can be variable. Some batches may
contain sensitisers (skin and respiratory).
The reaction with chlorine should be carried out in a fume cupboard.
Investigating natural oils.
(Y7)
(N8)
(S1)
Teacher/Technician
© ASE 2003 (adapted from Safety in Science Education, 1996 (HMSO) and Topics in Safety, 1988 & 1982
Chloroethene
The dust reacts violently with sulfur, iodine, manganese (IV) oxide, potassium chlorate(V)
and in general with oxidising agents. For reactions with iodine use coarse powder. Impure
granulated zinc is best for hydrogen preparation. Zinc metal is of low toxicity, but zinc
oxide fume from burning is harmful; only burn in a well ventilated room and only once or
twice on each occasion.
For abbreviations see Introduction
Zinc chloride
C, N
Y12
N13
S6
Zinc chromate(VI)
T, N, Carc 1
Not generally recommended
Zinc iodide (anhydrous)
C, N
Y12
N13
S6
Zinc nitrate
O, Xi
Y9
N10
S3
Zinc sulfate
Xi, N
Y7
N8
S1
Zinc sulfide
Xn, N
(Y8)
(N9)
(S2)
Not suitable for use in schools. The solid is not recommended for use in schools. The
production of a precipitate of zinc chromate on a small scale does not present a hazard
provided it is not filtered off and dried.
Ignites combustible materials; violent reactions with metals and reducing agents. Toxic
nitrogen dioxide evolved on heating. See Nitrates.
FC
© ASE 2003 (adapted from Safety in Science Education, 1996 (HMSO) and Topics in Safety, 1988 & 1982
Can liberate very toxic hydrogen sulfide on acidification.
If used as a substitute for Zinc Blende ore; roasting will produce much toxic sulfur dioxide.
Use fume cupboard for this activity.
For abbreviations see Introduction