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GIFT OF
PROF. W.3. RISING




WILLARD B. RISING



Mo.




TEXT-BOOKS OF SCIENCE



ADAPTED FOR THE USE OF



ARTISANS AND STUDENTS IN PUBLIC AND OTHER SCHOOLS.



QUALITATIVE CHEMICAL ANALYSIS
AND LABORA TOR Y PRA CTICE.



LONDON : PRINTED BY

SPOTTISWOODE AND CO., NEW-STREET SQUARE
AND PARLIAMENT STREET



SPECTRA Of THE METALS Of THE ALKALIES 3c ALKALINE EARTH!:



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A. B C D E T




In



QUALITATIVE

CHEMICAL ANALYSIS



AND



LABORATORY PRACTICE.



BY

T. E. THORPE, PH.D. F.R.S.E.

PROFESSOR OF CHEMISTRY

ANDEKSONIAN INSTITUTION, GLASGOW :

AND

M. M. PATTISON MUIR, F.R.S.E.



LONDON :
LONGMANS, GREEN, AND CO.

1874.

All rights reserved*



PREFACE.



THIS BOOK is divided into two distinct parts. In PART I.
the student is instructed to perform a series of experiments,
in order to familiarise himself with the leading properties of
the chief non-metallic elements, and of the principal sub-
stances which they form by their mutual union. This por-
tion of the book is, of course, supplementary to the work of
the lecture-room, and should be studied in connexion with a
manual in which the origin, properties, and relations of the
various bodies are fully described.

The experiments are generally of a very simple nature,
and are strictly illustrative of the chemical and physical
properties of the substances to which they refer. To each
lesson is appended a short statement or summary of the
facts which that lesson is intended to convey. The object
of these resumes is to afford the student precise ideas of
the nature and extent of the information which he has
gleaned from the experiments he has performed. The
advantages of this preliminary course are manifest. Not
only does the student become practically familiar with the
properties of a large number of chemical agents, but he
acquires opportunities for the exercise of manipulative skill
and dexterity in the construction and arrangement of appa-

237346



vl Preface.

ratus, which the few and simple operations of ordinary
qualitative analysis are not so well fitted to give. In
arranging this course of laboratory practice we have sought
to cover the Scheme of Practical Instruction sketched
out in the Syllabus of the Science and Art Department.

PART II. treats of Qualitative Analysis ; it is divided
into five sections.

In the first section the general preliminary operations of
testing are described, such as the employment of flame
reactions, the use of the Bunsen flame, the spectroscope, .
and so for'.h.

The second section treats of systematic qualitative
testing. The wet and dry reactions of each of the more
commonly occurring bases and acids, inorganic and organic,
are first described, after which a synopsis of analytical
methods is given.

The third section gives the special tests for the rarer
elements, and shows where they may be expected, and how
they may be separated, in the ordinary course of analysis.

The fourth and fifth sections have been added mainly
for the use of medical students.

We have endeavoured to make this book as practical as
possible. The methods of analysis are, of course, mainly
founded on established and reliable processes. Still the
book will be found to contain a number of novelties both in



Preface. vii

the way of shortening the course of systematic testing and
in the recognition of bodies by means of special tests. We
have hesitated, however, to adopt new methods, unless
experience has shown them to be preferable to the older
ones. All the experiments described in the First Part have
been carefully tried ; and with the exception of certain of
the separations of the rarer metals and organic poisons,
which, however, will be recognised as well-established pro-
cesses, all the operations described in the Second Part have
been repeatedly tested by ourselves and by students in this
Institution.

Our thanks are due to Mr. DUGALD CLERK and to
MR. STEPHEN MILLER for the attention they have bestowed
on the woodcuts.



CONTENTS.



PART I.

PREPARATION AND PROPERTIES OF GASES.
LIQUIDS, AND SOLIDS.



LESSON I.

PAGE

Oxygen Its Preparation Bending Glass Tubes^-Use of the
Pneumatic Trough Oxygen supports Combustion Distinc-
tive Character of Chemical Action Meaning of the Term
'Chemical Test' I



LESSON II.

Hydrogen Its Preparation Its Lightness Pouring Hydrogen
Upwards Formation of Zinc Sulphate Crystallisation of a Salt 9

LESSON III.

Combination of Oxygen with Hydrogen Composition of Water
Combustion of Oxygen in Hydrogen Combustion of Air in
Coal Gas Meaning of the term ' Combustion ' . . .12

LESSON IV.

Nitrogen - Its Preparation It does not support Combustion It is
not itself combustible It differs from Carbon Dioxide . .18



LESSON V.

Nitric Acid its Preparation Distillation Tests for Nitric Acid. 19



x Contents.

LESSON VI.

PAGE

Nitrogen Monoxide Its Preparation Meaning of the terms
' Neutralisation ' and ' Salt ' Nitrogen Monoxide supports Com-
bustion Difference between its Power of supporting Combus-
tion and that of Oxygen Difference between Nitrogen Monox-
ide and a Mixture of Nitrogen and Oxygen . . . -23

LESSON VII.

Nitrogen Dioxide Its Preparation Its Power of supporting
Combustion Difference between this and the Power of Nitro-
gen Monoxide Action of Oxygen on Nitrogen Dioxide
Analysis of Air . 27

LESSON VIII.

Ammonia Its Preparation Collection of Gases by Displacement
Combustion of Ammonia Slow Combustion of Ammonia
Formation of Ammonium Chloride Solubility of Ammonia in
Water 30

LESSON IX.

Carbon Dioxide Its Preparation Its Density Its Action on
Lime Water and on Litmus Solution It does not support Com-
bustion Decomposition of Carbon Dioxide Its Solubility in
Water It is absorbed by Caustic Potash Solution ... 36

LESSON X.

Carbon Monoxide Its Preparation Decomposition of Oxalic Acid
by means of Sulphuric Acid Separation of Carbon Monoxide
,and Dioxide Combustion of Carbon Monoxide . . .40

LESSON XL

Chlorine Its Preparation Its Affinity for Hydrogen Its Bleach-
ing Action Its Oxidising Action 43



Contents. xi

LESSON XII.



PAGE



Hydrochloric Acid Its Preparation It does not support Com-
bustion, nor is it Combustible It is soluble in Water Its
Action on Litmus Solution Synthesis of Hydrochloric Acid
Analysis of Hydrochloric Acid .... 47



LESSON XIII.

Bleaching Powder Its Preparation Theory of Bleaching
Hypochlorous Acid Its Preparation Potassium Chlorate Its
Preparation Its Properties Chlorine Tetroxide Its Prepara-
tion . . . -49



LESSON XIV.

Bromine Its Preparation Its Detection Preparation of Potas-
sium Bromide Solubility of Bromine in Water Combination
of Bromine with Phosphorus ....... 5 2



LESSON XV.

Iodine Its Preparation Sublimation Tests for Iodine Com-
bination of Iodine with Phosphorus With Sodium Separation
of Iodine from Bromine Hydriodic Acid Its Preparation
Its Properties Difference between this Acid and Hydrochloric
Acid . 55



LESSON XVI.

Hydrofluoric Acid Its Preparation Etching Glass Silicon Flu-
oride Its Preparation Its Properties Hydrofluosilicic Acid
Its Preparation Filtration Use of the Wash Bottle . . 59



LESSON XVII.

Methane Its Preparation Its Combustion in Air Products of
its Combustion Explosion of Mixture of Methane and Oxygen
Action of Chlorine upon Methane . 65



xii Contents.



LESSON XVIII.

PAGE



Ethene Its Preparation Its Combustion in Air Its complete
Combustion with Oxygen Its Action on Bromine and Chlo-
rine ......... 68



LESSON XIX.

Ethine Its Preparation Preparation of Cuprous Chloride
Detection of Ethine Presence of Ethine in Coal Gas .



LESSON XX.

Luminosity of Flame Density of Products of Combustion Zones
of Flame Extinction of Flame by Conduction of Heat by
Metallic Surfaces .



LESSON XXI.
Sulphur Its Crystalline Forms Test for Sulphur Allotropy . 77

LESSON XXII.

Sulphur Dioxide Its Preparation Its Bleaching Action Its
Liquefaction Its Oxidation Its Action on Iodine Sulphur
Trioxide Its Preparation Its Properties . . . -79

LESSON XXIII.
Sulphuric Acid Its Properties Its Action on Sugar . . .85



LESSON XXIV.

Sulphuretted Hydrogen Its Preparation Its Action on Metallic
Solutions .... 86



LESSON XXV.

Phosphoretted Hydrogen Its Preparation Its Inflammability . 88



Contents* xiii



PART II.

QUALITATIVE ANALYSIS.

SECTION I.

GENERAL PRELIMINARY OPERATIONS.

PAGE

Flame Reactions Bunsen Lamp Charcoal Splinter Reduction
and Oxidation of Substances Films on Porcelain Flame
Colours Coloured Glasses Spectroscopic Analysis Prelimi-
nary Dry Reactions ........ 9

SECTION II.

SYSTEMATIC QUALITATIVE ANALYSIS.

Grouping of the Metallic Bases Group Reagents Special Tests
for Members of Group I. Separation of Group I. . . .107

Special Tests for Members of Group II. and Separation of the
Group in

Special Tests for Members of Group III. and Separation of the
Group . H9

Special Tests for Members of Group IV. and Separation of the
Group 122

Special Tests for Members of Group V. and Separation of the
Group 126

Special Tests for Members of Group VI. and Separation of the
Group 128

Illustration of Separation of all the Groups in the Analysis of
Fahl Ore .130

Tests for Sulphuric Acid and Sulphates 1 34

,, ,, Hydrofluosilicic Acid and Silicofluorides . . -135
,, ,, Phosphoric Acid and Phosphates . . . . . 135

,, ,, Boric Acid and Borates 137

,, Oxalic Acid and Oxalates 137

,, ,, Hydrofluoric Acid and Fluorides . . . . .138

Sulphurous Acid and Sulphites 139

,, ,, Silicic Acid and Silicates , . , . . .139
, Carbonic Acid and Carbonates 141



xiv Contents.

PAGE

Tests for lodic Acid and lodates 141

,, ,, Thiosulphuric Acid and Thiosulphates . . . .141

,, ,, Hydrochloric Acid and Chlorides ..... 142

,, ,, Hydrobromic Acid and Bromides . . . .142

,, ,, Hydriodic Acid and Iodides . . . . ... 143

,, ,, Chlorides, Iodides, and Bromides, when occurring to-
gether 145

,, ,, Hydrocyanic Acid and Cyanides ..... 145

,, ,, Nitrous Acid and Nitrites ...... 147

Hypochlorous Acid and Hypoohlorites . . . . 14 7

,, ,. Hydrosulptiuric Acid and Sulphides- .... 148

,, ., , Nitric Acid and Nitrates . .... 149

, ,, Nitrates and Chlorates, when occurring together . .150

,, ,, Nitrogen in Organic Bodies . . . . . . 151

,, ,, Chloric Acid and Chlorates . . . . . . 151

,, ,, Perchloric Acid and Perchlorates . . . . . 151

,, ,, Tartaric and Citric Acids . . . . . .152

,, ,, Benzoic and Succinic Acids . . . . . . 153

,, ,, Acetic and Formic Acids . . . . . . 153

Synopsis of Analytical Methods :

Table for Preliminary Dry Tests 155

,, ,, Flame Reactions by the Bunsen Flame . . .156
,, ,, Solution of Substances . . . . . -157

,, ,, Treatment of the Solution . .. . . .158

, , , , Separation of Group I. . . . . . 1 59

J, H 1 60

,, HI 161

,, IV 162

MM ,, V 163

VI 164

,, ,, Preliminary Examination for Acids .... 165

,, ,, Grouping of the Inorganic Acids .... 166

,, ,, Separation of the Inorganic Acids .... 167

,, ,, Examination of Insoluble Substances . . .168

,, ,, Separation of Organic Acids . . . . .169



Contents. xv



SECTION ill.

DETECTION OF THE RARE ELEMENTS.

PAGE

Tests for Thallium 1 70

,, ,, Palladium, Rhodium, Osmium, Ruthenium, Platinum, and

Iridium . . . . . . . . .171

,, ,, Molybdenum and Selenium . . . " . . . 173
,, . Tellurium . . . . . . . . .173

,, ,, Zirconium, Cerium, Lanthanum, Didymium, and

Titanium . . . . . . . .174

,, ,, Uranium and Indium ... ... 176

,, ,, Vanadium, Lithium, Caesium, and Rubidium. . .177
Detection of the Rare Elements in the Systematic Course . . 1 78

SECTION IV.

DETECTION OF POISONS.

Detection of Phosphorus 182

,, ,, Arsenic by Dialysis . . . . . . .183

,, ,, ,, by Marsh's Process ..... 187

,, by Fresenius and Von Babo's Process . .192
,, ,, Mercury, Lead, and Copper ..... 195

,, ,, Antimony and Zinc . . . . . . 195

,, ,, Hydrocyanic Acid . . . . . . .196

,, ,, Oxalic Acid . . . . . . . . 199

,, Alkaloids by Method of Stas 200

,, ,, ,, ,, ,, Uslar and Erdmann . . 202

Special Tests for Veratrine, Aconitine, Brucine, and Colchicine . 204
,, ,, ,, Morphine and Strychnine ..... 206
,, ,, ,, Quinine ........ 207

Detection of Opium . . . . . . . . . 208

Identification of Blood Stains ....... 209



SECTION V.

EXAMINATION OF URINE AND URINARY CALCULI.

Examination of Healthy Urine 2lo

,, ,, Abnormal Urine ...... 210

,, ,, Urinary Calculi . . . . . . . 214

APPENDICES .219



QUALITATIVE
CHEMICAL ANALYSIS

AND

LABORATORY PRACTICE.

PART I.

PREPARATION AND PROPERTIES OF GASES,
LIQUIDS, AND SOLIDS.



LESSON I.

PREPARATION AND PROPERTIES OF OXYGEN.

TAKE a few crystals of potassium chlorate, place them in a
clean dry test-tube, and heat them gently over a small Bunsen
flame (see list of apparatus in Appendix). The salt begins to
spirt, then fuses. Now light a small splint of wood, blow out
the flame so as to leave the wood just glowing at the point,
plunge this into the tube in which you are heating the potas-
sium chlorate ; but do not allow the wood to touch the fused
salt in the tube. Note what takes place : the splint, which
only glowed when introduced into the tube, now bursts into
bright flame, with a slight explosion. Withdraw the splint,
blow out the flame, introduce it again into the tube; the same
brilliant light will be noticed. What does this teach us?

-L-* B



2 Qualitative Chemical Analysis.

That, by heating potassium chlorate, we have produced a
substance having the property of causing an almost expiring
flame to burn again more briskly than ever, which property,
as we can easily determine, the potassium chlorate does
not itself possess. This substance is oxygen gas. If
this oxygen has been produced from potassium chlorate,
then that salt must have undergone some change. Let us
put this to the test. Take a few crystals of the chlorate,
dissolve them in water in a test-tube (by shaking the tube,
the mouth being closed by the thumb), and to this solution
add a drop of a solution of silver -nitrate. Nothing seem-
ingly takes place, the liquid remains clear. Take now the
small quantity of potassium chlorate which you have heated
in the test-tube, dissolve this also in water, and add a drop
of silver nitrate solution ; at once a white solid forms in the
liquid, and this on shaking settles down to the bottom of the
tube, (such a solid substance, produced by the addition of
one solution to another, or, in some cases, by passing a gas
into a liquid, is called a precipitate). These different actions
of silver nitrate show us that the potassium chlorate has been
changed by heat. What we have after heating is potassium
chlorate minus oxygen, which, as we saw, goes off as a gas
(KC10 3 =KC1+0 3 ).

In heating the potassium chlorate you will notice that it
spirts, and gives up moisture, which, condensing on the
colder part of the tube, is liable to flow back on to the hot
portion, and so to crack the glass. Before preparing a quan-
tity of oxygen it is therefore necessary to dry the salt. To
do this, grind about 30 grams of potassium chlorate in a
mortar, place it in a porcelain dish which is supported on
a tripod over a very small flame, stirring it from time to time
with a glass rod until it is dry. The temperature to which it
is necessary to heat potassium chlorate before it parts with
its oxygen is so high that the glass vessel containing the salt
is very apt to crack, or at least to soften ; but by mixing with
the chlorate a small quantity of an infusible substance, as



Preparation of Oxygen. 3

sand, oxygen will be given off at a comparatively low tem-
perature. To facilitate the decomposition of the chlorate,
we generally use not sand, but manganese dioxide, which
acts more readily. Take about 5 grams of manganese
dioxide and set it drying, as you have done with the potas-
sium chlorate.

Meanwhile get ready an apparatus in which to prepare
and collect the oxygen. Take a flask such as is described in
the list of apparatus, No. i, clean and dry it ; to do this,
pour a little water into the flask, add a few small pieces of
filtering paper, rinse well, shake out the paper, rinse again
with water, and let the flask drain ; then heat it gently over a
flame, turning it round, and either suck or blow out the
heated air by means of a piece of glass tubing ; select a
good cork a very little larger than the neck of the flask,
soften it (by wrapping it in a piece of paper, and rolling it
several times under the foot upon the floor), and bore a hole
in it about 6 mm. diameter, with a round file. (See Note i.)
Choose now a piece of glass tubing about 85 cm. long and
very slightly wider than the hole in the cork. Light an
ordinary gas-burner, bring the tube at about 15 cm. from
one end into the flame, holding it parallel with the broadest
part (fig. i), and keep turning it round ; soon you will feel
the tube soften. Now
slowly bend it, as if you
were making a crook
like a shepherd's staff,
turning it in the flame
as much as possible, and
not hurrying the opera-
tion in the least. Some practice is required to make a neat
bend ; but if the flame be good, if you turn the tube inces-
santly, and if you bend it slowly, you will soon be able to
conquer any little difficulty which at first may present itself.
When bent, the tube should have the shape shown in fig. 2,
No. i. At about 15 cm. or so from the other end make

B 2




4 Qualitative Chemical Analysis.

another bend in the opposite direction, but do not make this
bend so sharp as the first (fig. 2, No. 2). In making this
bend, hold the tube so that you may look along it, and then
you will be able to make both bends in one plane. Now,
by means of a three-cornered file, make a scratch on the
tube about 10 cm. from the end (fig. 2, No. 2, c), and, by a
sharp pull, break the tube at this point. Holding the tube
in both hands, bring one end of it into a Bunsen's flame, the
tube being inclined at an acute angle with the flame (see fig.
2, No. i) ; keep turning it round until just the edge of the
tube begins to glow, then after a few moments (turning the
tube all the while) withdraw it, when you will find that the

FIG. 2.




rough edge is now perfectly smooth ; do the same with the
other end of the tube, and allow it to cool. The end a
(see fig. 2) is now to be gently fitted into the cork. By this
time the potassium chlorate and manganese dioxide will be
dry; these are mixed together in a mortar, the mixture placed
upon a piece of paper, and poured, by means of this, into the
'flask. Fit the cork with the bent tube into the flask and
support it by a clamp (see fig. 3).

To collect the gas, use the pneumatic trough and four
gas bottles. The trough is nearly filled with water, in
which a gas bottle is inverted so that the water may rush
into it, the air escaping as the water enters. Some little



Preparation of Oxygen. 5

management is required to fill the bottle completely, but
by raising the mouth the bottle lying on its side beneath
the water just above the surface, and then slowly de-
pressing it, the last bubble of air may be forced out.
When this is done, place the bottle mouth downwards to
one side of the trough, while you fill the other bottles in
the same way. Now place the flask on the retort-stand in
such a position that the lower end of the delivery tube
passes under the water just beneath the hole in the beehive



FIG. 3.




shelf of the trough. Everything being now ready (see fig. 3),
gently heat the flask, using at first a small flame ; the air in
the flask will be first of all expanded and driven out, bub-
bling up through the water in the trough. When the bubbles
begin t follow one another in rapid succession they may
be tested by bringing a glowing splint of wood over the
place where they stream up through the water. If the splint
bursts into flame, then we may begin to collect the gas. To
do this, move one of the bottles on to the beehive shelf, so
that its mouth is over the opening in this shelf; the gas will



6 Qualitative Chemical Analysis.

then rise into the bottle, displacing the water, which finds its
way into the trough. When full, depress the mouth of the
bottle somewhat further beneath the water, slip a small tray
under it, then lift the bottle, standing mouth downwards,
on the tray (which must contain a little water) out of the
trough, and set it aside.

Fill the other three bottles in a similar manner. In
heating the flask while preparing the gas, so regulate the
heat as to avoid any sudden rush of gas ; and whenever a
sufficient amount of oxygen has been collected, remove the
lamp and lift the end of the delivery tube out of the water,
othenvise, in cooling, the water will rush back into the flask
and crack it. The mass remaining in the flask may, when
cold, be easily washed out with water.

We will now proceed to examine the properties of the
oxygen we have obtained. By the preliminary experiment
with potassium chlorate heated in the test-tube we have
learned that a burning body when plunged into oxygen
burns with greatly increased activity. Oxygen is evidently a
supporter of combustion.

Experiment /. Take a small piece of phosphorus about
tne size of a pea, dry it carefully between folds of filtering
paper (see Note 2), and place it in the cup of a deflagrat-
ing spoon, set fire to the phosphorus by bringing it for a
moment into a gas flame, and plunge it into a bottle of
oxygen ; a brilliant white light, almost insupportably bright,
is produced, together with dense white fumes. (If the gas
bottle be made of thick glass, it is advisable to dilute the
oxygen in it with about one-third of its volume of air before
burning the phosphorus, as the great heat may crack the
Bottle. This may be done by depressing the bottle in the
trough, allowing one-third of the oxygen to escape, and then
lifting the bottle, mouth downwards, out of the trough, so
that the water which flowed in when the oxygen escaped,
may run out.) When the bottle is c6ol, remove the defla-
grating spoon, put a little water into the bottle, and shake



Properties of Oxygen. 7

it up ; the white fumes disappear, they are dissolved in the
water. Taste a few drops of the solution thus formed
you find it exceedingly sour or acid. Pour into the bottle
a few drops of blue litmus solution (reagents list, No. 27) ;
it turns red, showing the presence of an acid. What, then,
has this experiment taught us ?

(1) That substances burn in oxygen with great

energy.

(2) That a substance having totally different pro-

perties from either oxygen or phosphorus is
produced when these bodies combine together.
The colourless gas oxygen, and the yellow
wax-like solid phosphorous form, when che-
mically combined, a light snow-like mass,
which, when dissolved in water, gives rise to
a solution possessing an intensely sour taste.

Experiment II. Place a small piece of sulphur in the
deflagrating spoon, set fire to it, and bring it into a bottle
of undiluted oxygen ; it burns with a pale lavender-blue
flame, considerably more brilliant than when it burns in air.
After the combustion is over, remove the spoon, and note
the pungent odour of the substance formed, also the seeming
absence of anything in the bottle ; the product of combus-
tion is an invisible gas. Add a little water, shake the
bottle, and pour in a drop or two of blue litmus solution.
By its action on the litmus you see that an acid is present.

Experiment III. In the third bottle a small piece of
charcoal is burned, in the spoon. Note the comparatively
feeble light produced; the presence of the gaseous com-
pound formed is shown (i) by its extinguishing a lighted
taper when plunged into it ; (2) by its action on lime-water,
which, when added and the bottle shaken, becomes turbid,
owing to the gas in the bottle, known as carbon dioxide,



8 Qualitative Chemical Analysis.

CO 2 , combining with the lime (lime-water being a solution
of lime in water), and forming a substance, carbonate of
lime, or calcium carbonate, insoluble in water, and therefore
appearing as a solid, floating about in small particles in the
clear liquid, and thus rendering it turbid.

You have thus detected the presence of an invisible gas,
by presenting to it something with which it could combine
to form a new substance, having such characteristic pro-
perties as to be easily recognisable ; you have thus applied
a chemical test.

You have learned from these experiments :


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