analar standard

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'ANALAR'

STANDARDS

for

LABORATORY CHEMICALS

Incorporating improved standards

for the Analj tical Ke a gen ts

or i ginally designated as 'A.K.'

F O U R T H E D I T I O N '

{Revised and enlarge^

F o r m u l a t e d a n d i s s u e d j o i n t l y b y

T H E B R I T I S H D R U G H O U S E S L T D .

and

H O P K I N & W I L L I A M S L T D .

L O N D O N

1 9 4 9


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f\nx Edition Septemb er 1934

Second

E dition February 1937

Third Edition anuary 1944

Reprinted June 1946

Fourth Edition {revised and enlarged) 1949


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C O N T E N T S

A N A L A R

'

Chemicals

P R EF A C E T O F O U R T H E D I T I O N

F O R E W O R D TO F I R S T E D I T I O N

P R EF A C E T O F I R S T E D I T I O N

E X P L A N A T O R Y N O T E S .

' A N A L A R ' S T A N D A R D S

AP PE ND IX I . . .

(a) R eagents Us ed in Test in g

(b) Indicator Solu t ions .

(c) Standard Solutions .

APPENDIX

2 . Prepa rat ion of Stand ard Com parison Solu t ion

APPENDIX 3 . T h e L im i t Te s t for W ater

APPENDIX 4 . T h e Lim i t Te st for Arsenic

APPENDIX 5 . Elect rod eposi t ion of Me tals

" A N A L O I D S "

I N T E R N A T I O N A L A T O M I C W E I G H T S

INDEX

. . . . . .

•.

•

lut ion

PAGE

V-

ix-

x i

x i v -

I-

284-

' 288-

289-

-. 291-

-vii

- X

-xiii

xviii

-283

284

- 2 8 8

- 2 8 9

-291

-292

292 -293

• 293-

29s-

2 9 9

- 2 9 4

294

-296

297

-302


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N O T E

' AnalaR ' is a registered trade-mark and is the joint

property of The British Drug Houses Ltd. and Hopkin

& Williams Ltd . T he specifications published in this

volume are the joint copyright of the two Companies.

Eac^n Company, however, produces and markets

' A nala R' chemicals independently.


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PREFACE T O T H E F O U R T H E D I T I O N

For the present edition the book of ' AnalaR ' standards has undergone

the greatest enlargement and the most thorough revision since its first

publication in 1934. Specifications for fifty-eig ht new ' AnalaR ' chemicals

are include d. Some of these constitute simply an extension of the existing

range while others have been selected in accordance with two definite

objectives. In the first place it was considered desirable to' introduce a

fairly liberal selection of organic chemical reagents which fall generally into

two sub-classifications—(a) reagents for inorganic analysis, including the

detection and determination by gravimetric, colorimetric or other means

of both m etals and acid rad icals, and (&) reagents for the identification of

organic substances by the formation of derivatives of definite melting-

poi nts. It has been shown repeatedly that impu re reagents, particula rly in

class {a), caii give rise to errors and difficulties altogether out of proportion

to the actual amount of impurity present, and the need for a definite

Standard of pu rity is well established.- In th e second place it was considered

that a useful purpose would be served if the ' AnalaR ' range were made to

include at least one compound of each of the more common elements, the

range having been rather restricted, hithe rto, from this point of view. Th is

policy has been put into effect so far as seems reasonable and so far as

suitable compounds can be made available. The items that have served

fpr the introduction of additional elements are marked with an asterisk

in the list of additions that follows:

Am monium bromide Digitonin

Amm onium dichromate Dioxan

Am monium formate 3:5-Dinitrobenzoyl chloride

Benzaldehyde 2:4-Dinitrophenylhydrazine

K-Benzoiii oxime Diphen ylbenzidine

Benzyl-wo-thiourea . j^yw^-Diphenylcarbazide

hydrochloride "Diphenylthiocarbazone

*Beryllium sulphate aa'-D ipyridyl

Bism uth nitrate Ethyl cyanoacetate

w-Butyl alcohol Indigo carm ine

iio-Butyl alcohol Iodine pentox ide

Cadm ium acetate Iodine trichloride

Cadmium chloride 7-Iodo-8 -hydrox yquinoline-5-

*Caesium chloride sulpho nic acid

Calcium sulphate Isatin

*Ceric ammonium nitrate *Lithium sulphate

i-C hloro-2:4- dinitrobenzene /)-Nitrobenzoyl chloride

Chromium chloride Nitron

Cupferron o-Phenanthroline


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PREFACE TO TH E FO UR TH EDITION

Phos phorus pentachloride * Strontium chloride

Pyrogallol *Tellu ric acid

Salicylaldo3|ime *Thal lium sulp hate

*Selenium *Th orium nitrate

Semicarbazide hydrochloride *Titany l potassium oxalate

Silver sulphate o-T olidine

Sodium arsenate /)-Toluidine

Sodium diethyldithiocarbamate Triketohy drindene hydrate

Sodium hydrogen tartrate Urea

Sodium pyrophosphate Zinc acetate

* Sodium selenate Zinc powder

Only one ' AnalaR ' chemical has been disco ntinued in the present

edition . T his is Fe rric Chloride, An hydrou s. T he difficulty of preparing

a satisfactory product, the unstable nature of the substance, and the very

small demand for such a high quality, have contributed to this decision.

All the previously existing specifications have been critically reviewed

and many have been materially revised both in the light of progress in

analytical chemistry and under the guidance of our experience of users'

requirem ents. A large num ber of additional tests will be found and many

old tests are replaced by more modern technique s. Certain im proveme nts

of more or less general nature appear worthy of specific mention.

Specific solubility tests have been incorporated in almost every mono

graph . Refractive index tolerances have been included for most of the

organic liquids. Following the modern tre nd , specific gravities at

^5'5°l^5'5° have been replaced by weights per m illilitre at 20°. Fo r the

lower alcohols, however, the older expression has been retained because

the whole system of determination and dilution in current use is based

upon tables that employ it.

Assays are now^ given for a greater number of chemicals and newer

methods have been introduced wherever appropriate.

The technique of electrolytic deposition has been adopted for two

distinct purp ose s: for th e assay of certain metallic salts, and for the removal

of the principal metal from such salts so that traces of alkalis and alkaline

earths may be determined by the evaporation of the resulting solution.

These impurities were previously isolated by precipitating the heavier

metal as the hydroxide or sulphide and there can be no doubt that a

considerable proportion of the impurity was carried down by the pre

cipitate . W herev er possible, a single deposition has been made to serve

both for the assay and for the test for alkaUs.

In the iron salts alkalis are now determined after removal of the iron

by an extraction m etho d. Certain impurities can be determined most

expediently and accurately by the use of the polarograph and no better


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P R E F A C E T O T H E F O U R T H E D I T I O N VU

reason seems necessary for the in t roduct ion of that ins t rum en t ; i t has ,

therefore, been applied to the determination of nickel in cobalt sal ts, of

lead in copper, of copper, zinc and lead in ferrous sulphate and of zinc in

potass ium and sodiu m hydrox ides . An ex tension of polarogra phic m ethod s

is anticipated for the future.

T h e K ar l F ische r techniq ue for the determ inat ion of wa ter i s the f irst

real answer to a long-s tanding problem of the greates t importance, and

the method is now adopted in the specifications for al l organic l iquids

ame nable to th is tech niqu e. T h e li terature relat ing to the determ inat ion

of mois ture in acetone by the.Kar l F ischer method is conf l ic t ing and in

our own exper ience errat ic resu l t s are obtained . T h e procedu re has ,

therefore, not been applied to this substance.

We have found i t desirable to separate most of the phosphate and si l icate

tes ts tha t were previously carr ied out by the one react ion wi th th e mo lyb-

date reagent . Cer tain ions , unavoidably prese nt , were found to have d iverse

effects upon the reactions of the two impurit ies and the relat ive sensit i

vit ies did not always corresp ond w ith suitable l imits . In som e cases the

sil icate figure appeared only incidentally and has been omitted in the

new system. On the o ther hand phosp hate and s il icate tes ts have been

added to the specifications for the alkali carbonates and bicarbonates and

the caustic alkalis.

The in t roduct ion of new methods of greater sensi t iv i ty and greater

accuracy occasionally show s that the figure previously qu ote d as the ma x i

m um l imi t of the im puri ty , thou gh the m ost accurate in it s t ime accord ing

to the means then avai lab le for i t s determinat ion , was under -es t imated .

Where these circumstances have been discovered i t has been possible in

some cases to com pens ate b y an impr ove me nt in the .quality of the chemical

and thu s make i t possible to retain the lower figure for the l im it . In othe r

instances this has no t been imm ediate ly possible and an increased figure

has been g iven , though i t must be emphasized that the mater ia l now

supplied is at least equal in puri ty to that issued under the older standards.

T hi s is the case wit h respect to the nickel con tent of cobalt sal ts. I t is

fel t that these circumstances lend considerable support to the view,

always held by the com pi lers of ' AnalaR ' S tan dards , tha t the qua nt i

tat ive expression, of max im um limits or of ' actual batc h analyses ' can b e

safely interpreted only with reference to a specified method of test ing.


H O P K I N A N D W I L L I A M S L T D .

January 1949


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F O R E WO R D T O T H E F I R S T E D I T I O N

By the late Professor Jocelyn F. Thorpe, C.B.E., Ph.D., D.Sc, F.R.S.,

one time Professor of Organic Chemistry in the University of London

(Imperial College)

T

H ER E was a time , prior to I9 i4,.when those who worked in chemical

laboratories found that the only means by which they could rely

on the purity and homogeneity of their reagents and research materials

depende d on the reputa tions of a few well-known firms. Even so, the

consumer had in several instances to redistil or recrystallise the initial

material he proposed to use before he could be certain that it -possessed

the necessary degree of ' pu rity ' for his purp ose. Fo r the term ' purity '

is merely felative and can never be absolute, hence the necessity for some

criterion of ' p u ri ty ' which will give the user the information he

requires. T he statement that unreliable material yields unreliable resu lts

needs no emphasis. Ma ny research chemists have experienced the bitter

disappointment caused by the discovery that the work of many months

has been rende red useless by the presence of some ' alien' substance in the

material used. T he w riter remembers that on one occasion the presence

of phosphorus trichloride in a specimen of acetyl chloride obtained from a

well-known continental firm led to results which took some two months

to explain, and many research chemists must have had similar experiences.

There are cily two ways in which the consumer can be protected

against the unscrup ulous dealer or tra de r; either a specific standard mu st

be enforced as is the case with foodstuffs, etc., or the ' pu rity ' of the

materia} must carry with it the guarantee of some firm or combination

of firms of high standing whose reputations are bound up in the guarantee,

and who are prepared to inform the consumer exactly what is meant by

the word ' purity '.

The former method implies the policeman, and is one which Authority

alone can apply effectively. It is, moreover, one which A uthority is not

likely to apply unless the well-being of the public generally is concerned.

In the latter method the need for the policeman is replaced by the

reputation of the firm or firms supplying the materials, which acts as a

safeguard against any lowering of the standard desired and required by the

consum er. It was, therefore, und er the latter me thod that those who

controlled laboratories and research schools worked in pre-war times.

Th en came the war and everything was changed. It soon became

apparent that the number of reagents and research chemicals actually


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F O R E W O R D TO T H E F I R S T E D I T I O N

manufactured in th is country was exceedingly meagre, and that most of

them had been obtain ed f rom the con t inent . T h e cont ine ntal spr ing

having ceased to flow, the accumulated stocks in this country gradually

diminished or becam e local i sed unt i l a h ighly ser ious s i tuat ion arose. As

a t emporary measu re we a t t he Imper i a l Co l l ege , Sou th Kens ing ton ,

founded an Exchange Bureau through which Inst i tu t ions having large

quant i t ies of cer ta in substances could bar ter them for o thers of which they

mig ht s tand in urge nt nee d . At the same t im e the qua nt i ty of avai lab le

mater ia ls was increased by the preparat ion , by laboratory methods, of

those substanc es for wh ich there seemed to be the greates t dem and . Th is

method enabled us to t ide over a difficult period, but i t was obviously

to tal ly inade qua te to me et the requ irem ents of the s i tua t ion . For tu nate ly

Bri t i sh manufacturers soon began to provide the required mater ia ls in

the necessary quant i t ies and , as i s ment ioned in more detai l in the general

h is tor ical in t roduct ion which fo l lows th is Foreword , the quest ion of

pu r i ty was met by the adop t ion o f t he l e t t e r s ' A .R . ' ' A .R . ' mean t

' Ana ly ti ca l Re ag en t ' , bu t t o my min d i t a lso m e a n t ' Al l R ig h t ' . As a war

measure the scheme served i t s purpose, bu t , af terwards , i t fa i led because

it did Jiot faJJ Jj:to either of the categories mentioned above. It had neither

the supp or t of Au thor i ty nor the backing of rep uta t ion . In consequ ence

i t was ma de use of by al l and su ndr y to denote m ater ia ls of vary ing degrees

of pur i t y , and the le t ters ' A .R . ' soon ceased to have any reals ign i f icance .

I t i s , therefo re , w i th the greates t p leasu re, as wel l as p leasurable

ant ic ipat ion , tha t I lea rn from the book of wh ich th is is the Fore wo rd that

T he Bri t i sh D ru g Hou ses and Hopk in & W il l iams have agreed to i ssue

Lab orato ry Che micals of guarantee d ' pur i ty ' bear in g th e reg is tered

nam e ' A N A L A R ' wh ich wi l l serve as a guara ntee ba sed on the great

reputat ion en joyed by these wel l -known f i rms.

The book deals wi th some 200 substances , and in each case the physical

and che mical p rop ert ies a re given, in ord er tha t the degr ee of ' pu ri ty '

a t ta ined ma y be ind ic ated . In itself, apart from this, the book is a valuable

record of the ch ief prop er t ies of the substance s wi th wh ich it deals . I t

i s unde rs tood jthat fur ther com poun ds wi l l be added as c i rcumstanc es

requ i re .

Al l users wi l l wish the compi lers every success in thei r new enterpr ise .

J O C E L Y N T H O R P E

July 1934


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PREFACE T O T H E FIRST E D IT IO N

T

E first handbook describing definite tests and standards of puri ty

for chemical reagents would appear to have been Die Priifung der

chemischen Reagentien auf Reinheit

by C . Kra uch , pub l i shed in Germ any

in 188 8 . T h e publ icat ion of th is vo lum e was la ter taken .over by the f irm

of E. M erck , the la tes t ed i t ion of whose work was i ssued in 19 31. An

Engl ish t ranslat ion of Krauch ' s book was made by J . A. Wil l iamson ( then

chief chem ist to Bai rd & Ta t lock [L ond on] Ltd . ) and L . W . Du pr e in

1902 ,

bu t the manufac ture of reagen ts conforming to these speci ficat ions

o f pu r i ty r emained in Ge rm an han ds .

In 1914, the supply of Ger m an labo ratory chemicals being c u t off, a

jo in t com mit tee appoin ted b y the I nst i tu te of Chem ist ry and th e Society

of Publ ic Analysts drew up speci f icat ions of pur i ty , to which they appl ied

the le t ters ' A .R . ' signifying ' An alytical R eagen t ' , a designa tion w hic h

has s ince become wel l known throughout the Bri t i sh Empire by al l users

of pur e chemicals for scien t if ic purp ose s . T he n um be r of speci f icat ions

or ig inal ly i ssued by the jo in t commit tee in 1915 was 88 .

There was, however , a l ready avai lab le in th is country a book of speci

fications entitled

Analytical Reagents, Standards and Tests,

compi led by

Ed mu nd W hi te and pub l i shed in 1911 by Hopk in & W i l l i ams L td . , wh o

had been for ma ny years ma nufac tur ing and m ar ke t in g chemicals

comp lying wi th these tes ts . T hi s book contained mo nog rap hs relat ing to 137

substa nces . I t was repr in ted in 1916; a second edi t ion was publ ished

in 1925, and a th i rd ed i t ion in 1931.

The war- t ime need for Br i t i sh laboratory chemicals ( including analy t ical

reagents) was met by the strenuous efforts of the two firms most

d i rec tly concerned . Ho pk in & Wi l l i ams L td . con t inued to manu fac tu re

bot h to thei r own and to the ' A .R. ' specif icat ions; whi le T h e Bri t i sh

D rug H ouses L td . opened u p a spec ia l depa r tmen t fo r t he manufac tu re

of laboratory cherh icals . As a resu l t an adequate su pply of these chemica ls

was soon ensured to workers in th is country .

' In 1925 the B .D .H . app roa che d the two official bodies res pon sible for

the ' A.R. ' specifications with the suggestion that the specifications should

be rev ised and ex ten de d; bu t thei r rep ly was tha t thei r act ion had been

a war emergency measure and that they d id not wish to take any fur ther

par t i n th i s work . T h e B .D .H . then p roposed tha t t hey shou ld themse lves

carry out the wo rk; and th is they d id wi th the consent and a pprova l of


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XU P R E F A C E T O T H E F I R S T E D I T I O N

the Inst i tu te of Ch em ist ry and the Society of Pub l ic Ana lysts . T hi s

resu l ted in the publ ic at ion , in January 1926, of The B.D.H. Book of'A.R.'

Standards contain ing 158 specif icat ions wi th a prefatory no te wh ich had

been submit ted to and approved by the Counci ls of the two bodies men

t ione d . M eanw hi le Ho pki n & Wil l iams L td . had in 1925 issued a rev ised

edit ion of their book containing 144 specifications.

Subsequently the specifications of both firms have been further revised

and extended in the l igh t of increased exper ience and greater knowledge,

whi le the s tandar d of pu r i ty has been considerably raised . T hu s, in 19 31 ,

Ho pkin & W il l iams publ ish ed th e th i rd ed i t ion of thei r book c ontain ing

178 mo nog raph s, pre pa red and issued in co l laborat ion wi th Baird &

Tat lock (London) L td . , who had been themse lves p roduc ing ana ly t i ca l

reagents for some ten years . In 1932 the B.D .H . pub l ishe d the second

edit ion of thei r book, w hic h contain ed, in add it ion to revised riionographs

for the 158 chemicals in the first edit ion, new monographs for 50 other

substances , making a to tal o f 208.

The specifications published by the two firms, al though on similar l ines,

were not ident ical , and th is occasional ly led to misunders tanding on the

par t of users of labora tory chemicals . Of m uc h greater mo m en t , how ever ,

was the increasing ev idence that the le t ters ' A .R . ' we re being brou ght

into disrepute by the action of some firms in

(a )

app ly ing them ind i s

cr iminately to substances in respect of which no speci f icat ion exis ted ;

a n d (b ) issu ing chem icals label led ' A.R . ' which d id not conform to the

publ ished speci f icat ions . Profess ional chem ists , Un ivers i t ies , pub l ic ,

bodies and in fact al l cri t ical users of laboratory chemicals, fel t that the

designat ion ' A .R . ' was los ing the value wh ich at one t ime m ade th e te rm

syno nym ous wi th pu r i ty and rel iab i l i ty ; so tha t in me rely specify ing

' A .R . ' they could no longer re ly upo n get t ing m ater ia l of the requis i te

degree of pu r i ty . .

Acco rd ing ly , i t seemed des i rab le tha t t he B .D.H. and Hopk in &

Will iams should undertake the unification of their respective series of

specifications, so th at a definite s tand ard of puri ty sho uld b e av ailable

in th is cou ntry . T hi s pro ject has been carr ied out dur ing the past year by

co-operation between the chemists of the two firms, in the course of which

there has been conducted an extensive invest igat ion in to the technique of

detect ing min ima l quant i t ie s of imp uri t ies . T h e outc om e of th is

collaboration is the publication of the present book, the two firms being the

jo in t owners of the copyr igh t there in . T he w ork contains 220 specif ica

t i ons , and i s publ ished under the t i t le

'AnalaR' Standards for Labora tory Chem icals.

T hi s book provide s chem ists wi th a rev ised and up- to - da te ser ies of

specifications for laboratory chemicals which are sold by, and carry the


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P R E F A C E T O T H E F I R S T E D I T I O N XIU

guarantee of, both firms und er the trade-mark ' A na laR '. In the

preparation of the specifications full advantage has been taken of recent

advances in analytical practice, and many new and delicate tests have

been devised. Some of the former ' A .R.' specifications have been made

more stringent, others have been more accurately defined.

The vrord ' AnalaR' was chosen as a new designation to replace the

letters ' A .R.', wh ich, for the reasons already indicated, it was considered

desirable to discontinue. 'A na laR ' is a registered trade-m ark and is the

joint p roperty of the two firms. Use rs of ' AnalaR ' chemicals can feel

satisfaction and reassurance in the knowledge that the standards of purity

are definite and precise, and that all chemicals issued under this

designation are guaranteed by the two firms to conform to those sta nda rds.

T H E B R I T I S H D R U G H O U S E S L T D


September 1934


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E X P L A N A T O R Y N O T E S

Condit ions of Testing

The rout ine examinat ion of reagent chemicals over many years has

dem onst rated th e necessi ty for s tandard is ing the co ndi t ion s und er wh ich

limit tests for im pu rit ie s are carried ou t . I t has been recog nised th at tests

which give sat isfactory results in one laboratory may fai l in another

laboratory ow ing to sl ight differences in tec hn iqu e. In o rde r to avoid such

differences, part icular at tention has been paid to the wording of the tests

so that on ly , one in ter preta t ion can be p laced on the m .

The detai l s of the tes ts which have been 'worked out for the detect ion

of minute t races of cer ta in impuri t ies are descr ibed wi th par t icu lar care

so that consis ten t resu l t s may be obtained by analysts working indepen

dently in different labor atori es. T h e tests do not pro vid e against all

possible impurit ies, but do al low for al l those that have been found

significant in analytical practice.

Types of Tests Employed

Wherever possib le , methods have been used for determining the actual

amount of impuri ty present , bu t in tes t ing chemicals for ex t remely minute

amounts of impurit ies, i t is frequently impossible to specify the amount

present as a definite qu an ti tat i ve figure. T he re is a l imit ing sensit ivi ty

to al l tests, and where no reaction for an impurity is obtained, i t cannot

be s ta ted wi th cer ta in ty that the par t icu lar im pur i ty is abse nt . T h e

limiting values of such tests have been studied, and where no reaction is

observed , the amount of impuri ty present i s recorded as being less than the

minimum amount which under the condi t ions of the tes t g ives the fain tes t

possible reaction.

The tes ts for impuri t ies fa l l in to two groups:—

(i) T es ts in whic h th e m eth od is sufficiently sensit ive to afford a

true measure of the quanti ty of impurity present at , or even below, the

limit al lowed.

(2) Tests in which the amount of impurity sought is close to the

detectable threshold l imit imposed by the sensit ivi ty of the best

available method.

In th e first gro up are tests, such as the G utze it determ ination of

minute quanti t ies of arsenic, in which i t is easi ly possible to obtain

quanti tat ive results by matching the result of the experiment with suitable

stand ards. Fo r reaso ns given elsewhere in these notes, how ever, the

XIV


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E X P L A N A T O R Y N O T E S XV

individual monographs refer only to standards which represent the desired

l imits .

The second group embraces tes ts , typ i f ied by the su lphate and ch lor ide

tests ,

which do not lend themselves to quanti tat ive expression, and in these

tes ts the smal les t quant i t ies that can be detected under the condi t ions pre

scr ibed have, in most cases , been adopted as the maximum l imi ts of these

impu ri t ies . In th is connec t ion , it is o f ex t reme imp ortan ce that the con

dit ion s of the test be a dhe red t o, as, in ma ny ca ses, sl ight variat io ns in

technique may make considerable d i f ferences in the amount of impuri ty

which can be detected .

M a x i m u m L i m i t s o f I m p u r i t i e s

A statement of the maximum l imi ts of impuri t ies wi l l be found in each

mo nog raph . T h e f igures tha t are g iven are in tend ed to represen t the

am ount of im pur i ty that the tes t wi l l detec t . I t mu st be und ers to od , ho w

ever , that many tes ts that depend upon the comparison of opalescences ,

turb id i t ies and co lours are subject to cer ta in errors due to the d is turb ing

effect of the othe r subs tanc es in the solution. Fo r this and sim ilar reason s

the figures quoted cannot always be regarded as exact , and are subject to

rev is ion as the technique for the es t imat ion of very smal l amounts of

im puri t i es becomes mo re developed . Conse quent ly i t mu st be s ta ted that

the s tandards to which the chemical conforms are those of the actual tes ts ,

and the ' ma x imu m l imi ts of imp uri t ies ' are a ra t ional n iuner ical in ter

pretat ion of those tes ts . T hi s , of course, does not imply that the am oun ts

s tated are necessar i ly present in products conforming to the tes t , bu t the

f igures represen t the m ax im um permiss ib le l im i ts . T h e am oun ts of im

purit ies present in ' AnalaR ' chemicals are usually considerably less than

the maximum permiss ib le l imi ts , bu t th is addi t ional ref inement i s no t

regarded as being of much pract ical in teres t to the user .

T h e com pilers wil l at al l t ime s be grateful for any inform ation from

invest igators who have special i sed knowledge.

Reagent Solutions

T h e s t rengths of the reage nt so lu t ions employe d in the tes ts are ' g iven

in the A pp en dix . As far as possible these are describe d in ter m s of

norm al i ty or as molar so lu t ion s; th is makes for convenience and s impl ici ty .

The d i lu te acids and d i lu te a lkal i s are a l l approximately 5N, which i s a

convenient s t reng th for general us e; these are a lways referred to in t he

test as ' di lute acetic acid ' , etc . W he n th e word ' di lute ' is om itte d, i t is

in tended that the concentrated acid should be used .

T i m e

Where no length of t ime is s ta ted , a per iod of 5 minutes should be

allowed before observing the result of a test .


16/319

XVI E X P L A N A T O R Y N O T E S

Solubi l i ty Tests

In a few cases quantitative limits have been laid down for th e am ount of

insoluble m atter. In g eneral, it is required th at the substance shall give

a ' clear solution ' wh en a specified quantity is dissolved in a specified

volume of solvent. T hi s is to be interpreted as signifying a reasonably

clear solution as observed in the ordinary manner without the aid of

special instru m ents. No solid chemical substance prepa red com mercially

dissolves in a solvent to yield a solution in which particles of dust cannot

be detected, if sufficiently refined methods of observation be employed.

Usually, the proportion of insoluble matter is so small that a quantitative

determination by filtering off and weighing is quite unnecessary.

Tests for C hlorid es

The minimum opalescence which it is possible to perceive depends to

a large extent on the quality of the light under which the observation

is condu cted. In m any tests the expression ' no opalescence ' will be

foun d; this is intende d to mean an opalescence less tha n that produc ed

by the following procedure:—

To 50 ml. of water add o-i ml. of standard chloride solution (i ml. =

o-i mg. CI), I ml. of dilute nitric acid and i ml. of silver nitrate solution;

mix and observe after 5 minutes.

Tests for Residue

Where large quantities of reagents are used in carrying out a test it may

be necessary to apply a correction for the amount of impurity in the

reagents. T his applies particularly to the tests for alkalis and o ther metals

where the metallic radical of the salt is removed by precipitation and the

residue obtaine d on evaporation of the filtrate is ignited and w eighed. In

some cases it has been found that the residue from the reagents exceeds

that from the substance under examination. Fu rthe r, it must be

remembered that a filter paper may contribute to a filtrate soluble matter

weighing one milligram or an even larger amo unt. In orde r to obviate

inaccuracies due to such causes, it is essential that certain determinations

should be accompanied by blank experime nts carried out on the reagents

used so that the necessary corrections can be made.

Vo lu me t r i c S ta n d a rd s

Many substances have been proposed for the purpose of standardising

volumetric solutions. As the result of long exp erience in the laboratories

of the joint compilers, it is recommended that the following substances

only should be used as primary standards in work of high accuracy.

Potassium dichromate

Potassium hydrogen phthakite

Potassium iodate

Sodium carbonate (anhydrous)


17/319

E X P L A N A f O R V N O f E S XVII

Sodium chlor ide

Sod ium oxa l a t e

These are anhydrous sa l t s and they may be dr ied by heat wi thout change

of composi t ion.

T h e chemicals me nt ion ed below are of ten used for s tandard is ing

purposes , but they should be looked upon as be ing secondary s tandards .

Several contain water of crystal l isat ion and consequently are l iable to

gain or lose mois ture in accordance wi th the humidi ty of the a tmosphere

and the care wi th which they are s tored . Su ch sa lt s can not be dr ied

immedia te ly before use and consequent ly must be s tored in wel l -c losed

conta iners .

Ant imony po t a s s ium t a r t r a t e

Arsenious ox ide

Benzoic acid

Fe r rous ammonium su lpha t e

Guan id ine ca rbona t e

Hydraz ine su lpha t e

Oxalic acid

Po t as s ium hydrogen t a r t r a t e

Silver ni t rate

Sod ium bora t e

Chemicals for BuiYer Solutions

T h e fol lowing chem icals , specif icat ions for wh ich are inclu ded in th is

boo k, are sui tab le for pre pa rin g buffer solu t ions for us e

•

in the

determinat ion of hydrogen ion concent ra t ion.

Acet ic acid

Aminoacet ic ac id

Boric acid

Citr ic acid

Potass ium chlor ide

Po tas s ium d ihydrogen phospha t e

Po t as s ium hydrogen ph tha l a t e

Potass ium te t roxala te

Sodium chlor ide .

Sod ium phospha t e ( anhydrous )

A t o m i c W e i g h t s

Intern at ion al Atomic We ights , 1947, have been used in ca lcula t ing the

mo lecular weig hts , factors, etc. A table is given on page 29 7.

T e m p e r a t u r e s

are state d in Cen tigra de degrees and al l tests are con du cted

at room tempera ture (15° to 25°) unless o therwise s ta ted .

De t e rmina t i ons o f W e i g h t p e r m l . an d S p e c i f i c G r a v i t y de t e rmina t i ons

are based on weighings in air .


18/319

Xvii i feXPLANAl-ORY NOTES

B o i l i n g R a n g e T e s t s

are car r ied out in the appara tus and by the method

of the Br i t i sh Standard Speci f ica t ion No. 658—1936.

M e l t i n g P o i n t s are de termined on the f reshly dr ied mater ia l which,

conta ined in a sui table tube , i s in t roduced in to the heated bath l iquid

wh en the la t te r reaches a tem pera ture app rox imate ly 10° be low t he

ant ic ipa ted me l t ing po int . T h e l iquid i s heated so as to pro duc e a

temp era ture r i se of approx imate ly 2° per m inu te .

F r e e z i n g P o i n t s a r e de t e rmined by t he me thod desc r i bed i n t he Repor t

o f t he E ssen t i a l O i l Sub -Commi t t ee t o t he S t and ing Commi t t ee on

Uni fo rmi ty o f Ana ly t i ca l Me thods , Analyst, 5 4 , 335 (1929 ) .

I t has not been cons idered poss ible to acknowledge the many sources

of the tes t s descr ibed, d i s t r ibuted as they are through many sc ient i f ic

pub l ica t ions . Al l have bee n the subjec t of ex tend ed exp er im ent in the

B . D . H . and H . & W . Ana ly t ica l L abora to r i e s . M an y of the t e s ts a r e

or iginal and others have be en modi f ied to sui t the par t icular re qui re m ents

of the chemical for which they are used.




19/319

'ANALAR' STANDARDS FOR

LABORATORY CHEMICALS

A N A L A R

ACETIC ACID

(Glacial)

CH3.COOH = 60-05

Maximum Limits of Impurities

iNon-volatile Matter . . . o-ooi per cent .

Chloride (CI) . . . . . . 0-0002 per cent.

Sulphate (SO4) . . . . 0-0004 Per cent.

Heavy Metals (Pb) . . . . 0-0002 per cent.

Iron (Fe) . . . . . o-oooi per cent.

Bromine absorbed (Br) . . . o-oo6 per cent .

Oxygen absorbed from Dichromate (O) 0-003 P^r cent .

Arsenic (AsjOs) . . . . o-oooi per cent.

(i part per million)

1. Description.—A clear colourless liquid with a characteristic odour.

2 . Solubility.—Miscible in all proportions with water, and with alcohol,

forming clear colourless solutions.

3 . Freezing Point.—Not below 15-5°.

4 .

Non-volatile Matter.—Evaporate 50 ml. to dryness on a water-

bath. Not more than 0-5 mg. of residue should be left.

5 .

Chloride.

—Dilute 5 ml. with 45 ml. of water and add i ml. of dilute

nitric acid and i ml . of silver nitrate solution. No opalescence should

be produced.

6.

Sulphate.

—To 50 ml. add 0-2 ml. of N / i NagCOg and evaporate

to dryness on a wa te r-bath ; dissolve the residue in 10 ml. of water and

I ml. of N/i HCl, filter if necessary, and add i ml. of barium chloride

solution. Any turbidity produced should not be greater than the

" standard turbidity " defined in appendix 2.

7 .

Heavy Metals and Iron.

—Dilute 10 ml. with 30 ml. of water

and add 15 ml. of strong ammonia solut ion; cool and .pass hydrogen

sulphide through the solution for a few seconds. Any colour pro duced

should not be deeper than the " standard colours " defined in appendix 2.'

^

^Continued

overleaf)


20/319

ANALAR STANDARDS

ACE TIC ACID {Glacial)—continued

8 . B r o m i n e A b s o r p t i o n .— Int roduce 20 ml . i n to a 50 ml . g radua ted

stop pere d flask, add 25 ml. of wa ter and 5 m l. of an ap pro x im ate ly de ci-

no rm al solution of bro m ine in glacial acetic acid . Shak e and adjust with

wa ter to ex actly 50 m l. Pip ette off im me diate ly 10 m l. of thi s, add 20 ml.

of water and 5 ml . o f po tass ium iodide so lu t ion and t i t ra te the l iberated

iodine wi th N/ 50 NagSaO^ using s tarch as ind icato r . K ee p the rem ainde r

in a dark place at 20° for i hour and then t i trate a second 10 mJ. in the

same m an ner . T h e d if ference between the two t i t ra t io ns should not

exceed 0-15 ml.

9 .

O x y g e n A b s o r p t i o n .

— M ix 10 ml . wi th i m l . o f N / i o K aCrgO ,

and 10 n i l . o f su lphur ic acid , cool .and al low to s tand for 30 minutes ;

dilute with 50 ml. of water, again cool, add i ml. of potassium iodide

solu t ion and t i t ra te the l iberated iodine wi th N / i o NagSgOg. N ot less

than 0 -6 ml . o f N / i o NajSjOg sho uld be requir ed .

10.

A r s e n i c .

—Dilute 10 ml . wi th 50 ml . o f water , add 10 ml . o f

s tannate d hydroc hlor ic acid and tes t as descr ibed in appen dix 4 . Any

stain produced should not be greater than a o -o i mg. s tandard s ta in .

11. A s s a y .— D ilu te 2 to 3 g . wi th 50 ml . o f wa ter and t i t ra te w i th

N / i N aO H us ing pheno lph tha le in as ind ica to r .

I m l . N / i N aO H = 0 -06005 g . CH 3 .C O OH

Not less than 99-5 per cent , should be ind icated .

ANALAR

A C E T I C A N H Y D R I D E

(CH3.CO)_20 = 102-09

Maximum Limits of Impuri t ies

Non-volat i le Mat ter

Ch loride (CI) .

Sulphate (SO4)

Hea vy Me tals (Pb) .

Iron (Fe)

Phosphorus Compounds (P)

Organic Impu ri t ies .

0-0025 per cent,

o-ooi pe r cent .

0-002 pe r cen t.

0-002 pe r cen t,

o-ooi per cent .

0-0005 per cent,

passes test

1. D e s c r i p t i o n .— A clear colourless l iqu id wi th a pu ng en t odo ur .

2.

S o l u b i l i t y . —

Slowly soluble in water with formation of acetic acid.

Readily soluble in alcohol and in ether. •

3. W e i g h t p e r m l . a t

20°.—1-075 '^° ^•°^5 §•


21/319

F O R L A B O R A T O R Y C H E M I C A L S

4. Non-volati le Matter.

— Evaporate 20 ml. to dryness on a sand -ba th.

Not more than 0-5 mg. of residue should be left.

5.

Chloride.

—Dissolve 10 ml. in 40 ml. of water and add i ml. of

dilute nitric acid and i m l. of silver nitrate solution. Any opalescence

produced should not be greater than the " standard opalescence " defined

in appendix 2.

6. Sulphate.—Dissolve 5 ml. in 50 ml. of water, add i ml. of barium

chloride solution and allow to stand for 18 hou rs. No turbid ity or

precipitate should be produced.

7. Heavy Metals and Iron.—Dissolve i ml. in 40 ml. of water, add

10 ml. of dilute ammonia solution and pass hydrogen sulphide through

the solution for a few seco nds. Any colour produced should no t be deeper

than the " standard colours " defined in appendix 2.

8 . Phosphorus Compounds .—Boil 5 ml. with 10 ml. of water and

5 ml. of nitric acid; to the hot solution add 10 ml. of amm onium nitro -

molybda te solution and ma intain at about 40° for 2 hou rs. No yellow

precipitate should be produced.

9 .

Organic Impurit ies .

—(a) Dissolve 2 ml. in 20 ml. of water and

add 38 ml. of N / i N aO H . Th e solution should have no foreign odou r.

(b) Boil gently 20 ml. with 5 ml. of glycerol under a reflux condenser

for 1 ho ur ; evaporate off th e excess of anh ydride , cool, mix w ith 20 ml.

of dilute nitric acid and 30 ml. of water and allow-to stand for 30 minutes.

A clear solution free from flocculent matter should be obtained.

10. Assay.—Dissolve 2 g. in 50 ml. of N/i NaOH, allow to stand

for I hour and titrate with N / i HC l using phenolphthalein as indicator.

ml. of N/i NaOH used

:—i— '-^—;—r-n— = a

weight ot anhydride

Dissolve a further 2 g. in 20 ml. of dry benzene, cool in ice, and add

a cold solution of 10 m l. of dry aniline in 20 ml. of dry ben zene . Allow

to stand for i hou r, add 50 m l. of N / i N aO H , shake vigorously and titrate

with N/i HCl using phenolphthalein as indicator.

m l.

of N /i NaO H used ^ ^

weight of anhydride

then 10-2 {a — b) = per cent, of (CH3.CO)aO.

Not less than 95 per cent, should be indicated.


22/319

ANALAR STANDARDS

A N A L A R

ACETONE

(CHs)^CO = s8-o8


Acidity

Alkalinity

Non-volatile Matter

Oxygen absorbed (O)

Water .

O'l ml. N / I per cent.

O'l ml. N / I per cent.

0-002S per cent.

. 0-0005 per cent.

l-o per cent .

1. Description.—^A dear colourless liquid with a characteristic odour.

2. Solubility.—Miscible in all proportions with water forming clear

colourless solutions.

3 . Acidity.—Dilute 10 ml. with 10 ml. of carbon dioxide-free wate r,

add o-i ml. of phenolph thalein solution and titra te with N/ i o Na OH .

Not more than o-i ml. of N/io NaOH should be required to produce a

pink tint.

4 .

Alkalinity.

—D ilute 10 ml. with 10 ml. of water, add o-2 ml. of

methyl red solution and titrate with N / i o HCl . Not more than o-i ml.

of'N/io HCl should be required to produce a red tint.

5.

Weight per ml. at 20°.—0790 to 0792 g.

, 6. Refractive Index.—nf

1-3580

to 1-3600.

7 . Boiling Range.—Not less than 95 per cent, should distil between

56-0° and 56-5°.

8. Non-volatile Matter.—Evaporate 50 ml. to dryness on a water-

bath. Not more than i mg. of residue should be left.

9.

Oxygen Absorption.

—To 20 inl. Md o-i ml. of N / io KM n0 4

and allow to stand for 15 min ute s. Th e pink colour should not entirely

disappear.

10.

Water.—To 2 ml. add 10 ml. of carbon disulphide. A clear solution

should be produced.

A N A L A R

ACETYL BROMIDE

CHs.COBr = 122-96


Non-volatile Matter . . . o-oi per cent.

Sulphate (SO4) . . . . 0-002 per cent.

Phosphorus Compounds (P) . . 0-0025 P^r cent.

I. De sc ri pt io n. —A clear colourless or slightly yellow liquid, Th e


23/319

FOR LABORATORY CHEMICALS 5

product as issued contains small amounts of acetic and hydrobromie

acids.

2 .

Solubility.

—Decomposed by water with formation of acetic and

hydrobromie acids.

3 . Non-volatile Matter.

—Evaporate lo ml. to dryness on a water-

bath. Not more than i mg. of residue should be left.

4 . Sulphate.—Disso lve 5 ml. in 50 ml. of water, add i ml. of bar ium

chloride solution and allow to stand for i hour. No turb idi ty or precipitate

should be produced.

5. Phosphorus Compounds.—Treat i ml. cautiously with i ml.

of water, add i ml. of nit ric acid, boil, cool, add 20 ml. of water and

10 ml. of ammonium nitro-molybdate solution and maintain at about

40° for 2 hours. No yellow precipitate should be prod uced.

6.

Assay.

—Dissolve i g. in 50 ml. of N / i Na OH and titrate with

N / i H2SO4 using phenolphthalein as indicator.

I ml. N / i Na OH = 0-06148 g. CH^.CpBr

Not less than 97-5 per cent, should be indicated.

Dilute the neutralised liquid with water to produce 250 ml. and titrate

50 ml. of this with N/io AgNOg, using potassium chromate as indicator.

I ml. N/io AgNOs = 0-0123 g- CHg.COBr


A N A L A R

ACETYL CHLORIDE

CH3.COCI = 78-50


Non-volatile Matter

Sulphate (SO4)

Phosphorus Compounds (P)

Heavy Metals (Pb) .

Iron (Fe)

o-oi per cent .

0-002 per cent.

0-0025 per cent,

o-ooi per cent .

0-0005 per cent.

1. Description.—A clear liquid, colourless or not more than very

slightly yellow. Th e product as issued contains small amounts of acetic

and hydrochloric acids.

2 .

Solubility.

—Decomposed by water, with formation of acetic and

hydrochloric acids and forming a clear colourless solution.

3 . Boiling Range.

—Not less than 95 per cent, should distil between

50° and 52°.

4 .

Non-volatile Matter.—

Evaporate 10 ml. to dryness on a water-

ba th . No t more than i mg . of residue should be left.

{Continued overleaf)


24/319

A N A L A R S T A N D A R D S

ACETYL CHLORIDE—continued

5 . S u l p h a t e .— D isso lve 5 ml . in 50 ml . o f water , add i m l . o f bar iu m

chlor ide so lu t ion and allow tp s tand for i ho ur . N o turb id i ty or precip i ta te

shou ld be p roduced .

6 .

P h o s p h o r u s C o m p o u n d s .

— T re at i ml . cau t iously wi th i ml . o f

water, add i ml. of ni tr ic acid, boil , cool, add 20 ml. of water and 10 ml.

of ammonium ni t ro -molybdate so lu t ion and main tain at about 40° for

2 ho urs . N o yel low prec ip i ta te should be pro duc ed .

7 . H e a v y M e t a l s a n d I ro n .

—Dissolve 2 ml . in 35 ml . o f water , add

15 ml . o f d i lu te ammonia so lu t ion and pass hydrogen su lphide through

the so lu t ion for a few sec ond s. An y colour prod uce d shou ld not be deep er

than the " s tandard co lours " def ined in appendix 2 .

8 .

A s s a y .

— Dis so lve i g. i n 50 ml . o f N / i N aO H and t i tr a t e wi th

N / i H2SO4 us ing pheno lph th a le in as ind ica to r .

I m l . N / i N a O H = 0 -03925 g . CH3.COCI

Not less than 98 per cent , should be ind icated .

Di lu te the neut ral i sed l iqu id wi th water to produce 250 ml . and t i t ra te

50 ml . o f t h i s wi th N / i o A gNOg us ing po tass ium ch rom ate as ind ica to r .

I m l , N / i o A g N O s = 0 -00785 g . CH3.COCI


ANALAR

A L U M I N I U M A M M O N I U M S U LP HA TE

(Ammonium Alum)

AlNH4(S04)2 . i2H20 = 453-33

Max imum Limi t s o f Impur i t i es

C hloride (CI) . . . . . 0-004 Per cent .

H eavy M eta ls (Pb) . . . . 0-004 p e r cent.

I ro n (Fe) . . . . . o-ooi p e r cen t.

Alkalis and Alkaline Ea rths (Na) . 0-03 pe r cent .

1.

D e s c r i p t i o n .

— Co lou r les s crystals or a crystal l ine po w der .

2.

S o l u b i l i t y .

— D iss olv e 5 g. in 50 ml . of wa ter. A clear colourless

so lu t ion should be produced .

3 . C h l o r i d e .— D iss olv e 2-5 g. in 50 m l. of w ate r an d add i m l. of

dilute nitr ic acid and i m l. of si lver nitra te solu tion. An y opalescence

prod uce d should not be greater than the " s tan dar d opalescence " def ined

in appendix 2 .

4 .

H e a v y M e t a l s .

—Dissolve 0 -5 g . in 50 ml . o f water , add 2 ml .

of sodium hydroxide so lu t ion and pass hydrogen su lphide through the

solu t ion for a few sec ond s. Any colour prod uce d should not be deeper



25/319

FOR LABORATORY CHEIVlICALS

5 .

I r o n .— Dis solve i g . in 10 m l. of wa ter an d i m l. of di lute

hydroch lor ic acid and ad d i d rop of N / i o K ]Vfn04; mix , add 5 ml . o f

ammonium th iocyanate so lu t ion and 10 ml . o f a mixture of equal vo lumes

of amyl alcohol and amyl acetate, shake vigorously and al low to separate.

Any colour produced in the upper layer should not be greater than that

prod uce d by t reat ing i ml . o f s tand ard i ron so lu t ion ( i m l . = o -o i m g.

Fe) in the same manner .

6 . A l k a l i s a n d A l k a l i n e E a r t h s. —Dissolve 5 g. in 100 ml. of

hot water , add 10 ml . o f d i lu te amm onia so lu t ion , bo i l gent ly for 2 mi nut es

and fil ter. Ev apo rate 55 m l. of the fil trate to dryn ess and ignite the resid ue

gent ly . No t more than 2 -5 m g. should be obta ined .

7 . A s s a y .

—Dissolve 2 -5 g . in 250 ml . o f water , add 2 g . o f ammonium

chlorid e and heat to boil ing. A dd a sl ight excess of dilut e am mo nia

solution , boil gently for 3 m inu tes , allow to stand for 10 m inu te s, f il ter,

wash with water, ignite at 1100° and weigh.

W eig ht of AI2O3 X 8-894 = weigh t of AlN H4(S 04)2 . i2H 20

Not less than 99-5 per cent , should be indicated.

A N A

LA R

A L U M I N I U M O X I D E

(Calcined)

AI2O3 = 101-94

Maximum Limits of Impufi t ies

Ch loride (CI) 0-005 pe r cen t.

Su lpha te (SO4) . . . . o-oi pe r cen t .

Iro n (Fe) O'Oi pe r ce nt.

Loss on Ignitio n . . . . i-o p er cen t.

1.

D e s c r i p t i o n .— A du l l wh i t e powder ,

2 . S o l u b i l i t y .

— Inso lub le in wate r an d ' i P d i lu t e ac id s . Par ti a lly

so luble in sodium hydroxide so lu t ion .

• 3 .

C h l o r i d e . —

B oi l 2 g. w ith 50 m l. of Wiiter and i m l. of dil ute

nitric acid, cool and filter and to the filtrate add i ml. of silver nitrate

so lu t ion . Any opalescence prod uce d should not be greater than the

" s tandard opalescence " def ined in appendix 2 -

4 . S u l p h a t e . —

Bo il i g . wit h 50 ml . of wa ter a nd i ml . of di lu te

hy dro ch loric acid , cool an d filter and to the filtrate ad d 1 m l. of b ar iu m

chlor ide so lu t ion and al low to s tand for i h our . No turb id i ty or pre cip i ta te


5.

Iron.—Boil o-i g . w ith 10 m l. of wate r and] i m l. of di lute hy dr o

chloric acid, cool and fil ter; to the fil trate add i dr op of N / i o K M n 0 4 ;

mix , add 5 ml . o f am mo niu m th iocyanate so lu t ion and 10 ml . of a mix ture

(Continued

overleaf)


26/319

ANALAR STANDARDS

ALUMINIUM OXIDE

{Calcined)—continued

of equal volumes of amyl alcohol and amyl acetate, shake vigorously and

al low to sepa rate . Any colour prod uce d in the upper layer shou ld not

be greater than tha t produc ed by t reat ing i ml . o f s tand ard i ron so lu t ion

(i m l. = O'Oi m g. Fe) in the sam e m an ne r.

6 .

Loss on Igni t ion .

— H ea t i g . to i io o° . T he loss in weight should

not exceed lo mg.

ANALAR

A L U N I N I U M P O T A S S I U M S U L P H A T E

(Potassium Alum)

AlK(S04)2 . i2H20 = 474-39


C hloride (CI) . . . . 0-002 p e r cent.

He avy M etals (Pb) . . . 0-004 P^r cen t.

Iro n (Fe ) . . . . . 0-001 pe r ce nt.

A m m onia (NH3) . . . . 0-025 p er cent.

1.


—Colour less crystals or a crystal l ine powder .

2. S o l u b i l i t y .— D iss olv e 5 g. in 50 ml. of wa ter. A clear colourless


3 . C h l o r i d e .— D iss olv e 5 g. in 50 ml . of wa ter and add i m l. of

dilute nitr ic acid and i m l. of si lver nitra te solution . An y opalescen ce

produced should not be greater than the " s tandard opalescence " def ined

in appendix 2 .

4 . H ea vy Meta ls .—-Dissolve 0-5 g. in 50 ml. of water, add 2 ml.


solu t ion for a few second s. An y colour produ ced should not be deeper

than the " s tand ard co lours " def ined in appendix 2 .

5 . Iron.—Dissolve i g . in 10 ml. of water and i ml. of di lute hydro

ch lo ri c ac id and add i d rop o f N / i o K M n 0 4 ; m ix , add 5 ml . o f

ammonium th iocyanate so lu t ion and 10 ml . o f a mixture of equal vo lumes

of amyl alcohol and amyl acetate, shake vigorously and al low to separate.


pro duc ed by treatin g i m l. of sta nda rd iron solution (i ml . = o-oi m g. Fe )

in the same manner .

6 .

A m m o n i a .

—Dissolve 5 g . in 50 ml . o f water , add 20 ml . o f sodium

hyd rox ide solution a nd d ist i l 25 m l. , collecting the dist i l late in 10 m l. of

N / i o H2SO4 . T i t r a t e the excess o f ac id wi th N/ io N aO H us ing me thy l

red as ind icator . No t less than 9 -2^ ml . o f N / i o N ^O H should be re

qu i red .


27/319

F OR L A B O R A T O R Y C H E M I C A L S

7 . A s s a y .

—Dissolve 2 -5 g . in 250 ml . o f water , add 2 g . o f ammonium

chloride and heat to boil ing. A dd a sl ight ex cess of dilut e am mo nia

solution , boil gently for 3 minu tes , al low to stand for 10 m inu tes , f il ter ,


W eight of AI2O3 X 9-307 = weight of A lK (S 04) 2 . i2 H 20

Not less than 99-5 per cent , should be indicated.

A N A LA R

A L U M I N I U M S U L P H A T E

Al2(S04)3.xH 20 (x = a pprox imate ly 18)


Chlo ride (CI) .

Heavy Me tals (Pb) .

Iron (Fe)

Alkalis and other Metals (Na)

Ammonia (NH3)

o-ooi per cen t.

0-004 per cen t.

0-0025 per cent.

0-2 pe r ce nt.

0-02 pe r cen t.

1.

D e s c r i p t i o n .— Damp wh i t e c ry s t a l s o r powder .

2. S o l u b i l i t y .

— Dis solv e 5 g . in 50 ml . o f water . T h e so lu t ion should

not be more than s l igh t ly turb id .

3 . C h l o r i d e .— D iss olv e i g . in 50 ml. of wa ter and ad d i m l. of

dilute nitr ic acid an d i ml. of si lver nitra te solution. N o opalesc ence


4 .

H e a v y M e t a l s .—Dissolve 0 -5 g . in 48 ml . o f water , add 2 ml .


solu t ion for a few seco nds. Any colour produ ced sho uld not be deep er


5 .

Iron .— Dis solve i g . in 10 ml. of wa ter an d i m l. of di lute hy dr o

ch lo ri c ac id and add i d ro p of N / i o K M n 0 4 ; mix , add 5 ml . of

am m oniu m th iocyanate so lu t ion a nd 10 ml . o f a mix ture of equa l vo lum es

of amyl alcohol and am yl ac eta te; shake vigorously and al low to sepa rate .


produc ed by treat ing 2 -5 m l . o f s tand ard i ron so lu tion ( i m l . = o -o i m g.

Fe) in the same manner .

6 .

A l k a l i s a n d o t h e r M e t a l s .

— Di ssolv e 2 g . in 50 ml . o f ho t wa ter ,

add 10 ml. of di lute ammonia solution, boil gently for 2 minutes and

filter. Ev ap ora te 30 m l. of th e filtrate to dry nes s an d ignite th e res idue

gent ly . N ot mo re than 10 m g. should be obtain ed .

7 .

A m m o n i a .—Dissolve 5 g . in 50 ml . o f water , add 20 ml . o f sodium

hyd rox ide s olution a nd dist i l 25 ml. , collecting the dist i l late in 10 m l. of

N / i o H2SO4. T i t r a t e the excess ac id wi th N / i o Na O H us ing methy l

{Continued

overleaf)


28/319

1 0

ANALAR STANDARDS

ALUMINIUM SULPHATE—continued

r ed as ind ica to r . No t less than 9 -4 m l . o f N / io N aO H shou ld be r e qu i re d .

8 . A s s a y .—Dissolve 1-5 g. in 250 ml. of water, add 2 g. of ammonium

chloride an d hea t to boil ing. A dd a sl ight excess of dilute am mo nia

solution, boil gently for 3 m inu tes , al low to stan d for 10 m inu tes , f il ter ,


W eig ht of AI2O3 X 3-358 = we ight of Al2(S04)3

Not less than 51-0 per cent , and not more than 54-5 per cent , should be

indicated .

A N A

LA R

A M I N O A C E T I C A C I D

N H j . C H s . C O O H = 7 5 - 0 7


Sulphated Ash

Ch loride (CI) .

Sulphate (SO4)

Heavy Metals (Pb)

Iron (Fe)

Ammonia (NH3)

0-05 pe r cent,

o-ooi per cent .

0-005 per cent.

0-002 per cent.

0-001 per cent.

0-005 per cent .

1. Descr ip t ion .—^A whi te crystal l ine powder .

2. Solubi l i ty .

—-Dissolve 5 g . in 50 ml . o f water .

A clear colourless

so lu t ion should be produced ,

3 . R e a c t i o n .— Dis solve i g , in 100 ml , o f carbo n d ioxide- f ree

wate r . T o 50 ml . o f t he so lu t ion add o - i m l . o f N / i o N a O H ; the

pR

of

the resu l t ing so lu t ion should not be less tha n 6 -5 . T o th e o ther 50 m l . o f

the so lu t ion add o - i ml . o f N / i o H C l; the ^ H of the resu l t ing so lu t ion

should not be greater tha n 5 -5 . Us e brom ocresol pur p le as ind icator in

bo th t es t s .

4 . S u l p h a t e d A s h .— M ois te n 2 g . wi th su lphu r ic acid and igni te

gen t ly . N ot mo re tha n i m g. of res idue should be lef t .

5 . C h l o r i d e .

— Dis solv e i g . in 50 ml . o f wa ter an d ad d i m l . o f

dilute nitr i c acid an d i ml. of si lver nitra te so lut ion . N o opalescenc e


6 . S u l p h a t e .—Dissolve 2 g. in 50 ml. of water, add i ml. of di lute

hydrochlor ic acid and i ml . o f bar ium chlor ide so lu t ion and al low to

stand for i hou r . N o turb id i ty or precip i ta te should be prod uc ed .

7 . H e a v y M e t a l s a n d I r o n.

— D i s s o l v e 1 g, in 45 ml. of water,

add 5 m,l. of d i lu te am mo nia so lu t ion and pass hydrog en su lphid e throu gh


29/319


I I

the so lu t ion for a few seco nds. An y colour prod uce d should no t be deep er

than the " s tand ard co lours " def ined in appe ndix 2 .

8 .

A m m o n i a .

—Dissolve i g . in 45 ml . o f water , add 5 ml . o f sodium

hydro x ide solution an d dist i l 15 m l. T o the dist i llate add 35 m l. of wate r

and 2 ml . o f Ne ssler ' s reagent . An y colour prod uce d should not exceed

that given by the addit ion of 2 ml. of Nessler 's reagent to 50 ml. of

water contain ing 5 m l . o f s tan dar d am mo nia so lu t ion ( i m l . = o -o i m g .

NH3) .

9 . A s s a y .— D ige st 0 -3 g . wi th 10 ml . of su lphu r ic acid in a K jeldahl

flask unt i l colour less ; cool, add 150 ml . of wa ter and 100 m l. of sod ium

hydroxide solution, dist i l the l iberated ammonia and collect i t in 50 ml.

o f N / i o HC l . T i t r a t e the excess o f ac id wi th N / i o N a O H us ing me thy l

red as ind icator .

I m l . N / i o H C l = 0 -007507 g . NH 2 .CH 2 .CO OH


A N A LA R

A M M O N I A S O L U T I O N

(about 35 per cent . NH3)

N H 3 = 17-03



Chloride (CI)

Su lpha te (SOJ

Sulphide

Phosphate (PO4)

Silicate (SiO.j)

Carbonate (CO3)

Heavy Metals (Pb)

Iron (Fe) .

Tar ry Mat t e r

Oxygen absorbed (O)

Arsenic (AS2O3)

0-002 pe r cen t,

o-oooi pe r cent .

0-0005 pe r ce nt,

passes test

0-O0O2 pe r ce nt ,

o-ooi per cent .

0-003 pe r ce nt.

0-00002 pe r cent,

o-ooooi pe r cent ,

passes test

o-ooo8 pe r cent .

0-000005 per cent.

(0-05 part per mill ion)

colour less l iqu id wi th a s t rong pungent

. D e s c r i p t i o n .

—A clear

odour .

2. Spec i f i c Gravi ty .

—^About 0 -880 .

3 .

N o n - v o l a t i l e M a t t e r .

—Evaporate 100 ml . to dryness on a water -

bath . N ot more than 2 m g. of res idue should be lef t .

4 .

C h l o r i d e .— Eva pora te 10 ml . on a wa te r -ba th un t i l r educed to

I ml. , di lute w ith 50 m l. of wa ter and add i ml. of di lute nitr ic acid and

I ml . o f s i lver n i t ra te so lu t ion . No opalescence should be pr odu ced .

{Continued

overleaf)


30/319

19

fe l t the year 1932 'may safe ly be taken as the d iv id ing l ine o f p re -de -

press ion f rom post depress ion deb ts .

B ut th e pr incip le ado pted in the scal ing do w n of de bts is t he

pr inc ip le o f 'damdupat ' which says tha t when a c red i to r rece ives tv . ' i ce

the amount o f p r inc ipa l by way of p r inc ipa l o r in te res t towards deb ts

con trac ted be fore 1st Oc tober , 1932, the w hole of the de bt wil l be

deem ed to be d ischarged . Th us the p r inc ip le of 'dam dup at ' which i s

intended to be applied in the case of usurious rates of in terest is wrongly

app lied to slum p in pr ices . If scal ing dow n of debts is to be rela ted to

fa l l in p r ices a lone a ra t io be tween pr ices and deb ts should be es tab l i sh

ed and on this basis deb ts shou ld be scaled dow n. This ha s been th e

pr inc ip le in some fore ign cou ntr ies . B ut in M adra s it has been prove d

conclus ive ly tha t ances t ra l deb ts wi th usur ious ra tes o f in te res t a re the

heav ies t bu rd en on the agr icu l tu r is t s . If th is bu rd en i s to be rem ove d

the p r inc ip le o f 'damdupat ' shou ld be cor rec t ly app l ied .

The second c lass o f deb ts—the post depress ion deb ts—are dea l t wi th

differently . In th e case of thes e deb ts pa st pa ym en ts in exce ss of 5%

interest shall go to cover only arrears of in terest and not pr incipal

though the Se lec t Commit tee recommended tha t i t shou ld cover the

principal a lso . Here again i t is d iff icult to relate the reduction of

in te res t to any pr inc ip le . I t ha s no re la t ion e i ther to changes in th e

pric e leve l or capac ity to pa y. M oreo ver , th e ra te of in t ere st for al l

future debts is 6%% and as pr ices are gently r ising there is no just if ica

t ion for a lower rate of in terest f ixed for post-depression debts.

The scal ing down of debts on the basis of slump in pr ices can be

just if ied if the scal ing down were to be fol lowed by immediate discharge

of th e debts. B ut in th e abs enc e of any such facil i t ies de bto rs wil l be

pu t to g rea t har dsh ip . Fo r c red i to rs may wai t fo r a r i se in p r ices o r

they may press fo r immedia te se t t lement o f deb ts by tak ing over the

lan ds of debto rs. Th is can, to a cer tain ex ten t , be "mit igated if provi

s ions a re made to t ransfer lands to c red i to rs a t the p re -s lump pr ices and

to exempt a min imum hold ing in the case o f agr icu l tu r is t s who cu l t iva te

the i r own lands .

But as there are many diff icult ies in the way of scal ing down debts

in relat ion to fal l in pr ices, as condit ions in Madras are favourable mainly

for the applicat ion of the pr in cipl e of 'dam du pat ' , i t wil l be r ig ht to re ve rt

to th e pr incip le of scal ing dow n embod ied in th e or iginal bi l l . I t ma y

be laid down that a l l debts contracted before 1st October , 1937, and

which car ry more than 5% in te res t s imple o r compound sha l l be sca led

dow n on ^ e bas is of the p r inc ip le of 'dam dup at ' . Fo r al l deb ts con t rac t

ed af ter that date and for al l future debts the rate of in terest shall be


31/319


3

A N A

LA R

A M M O N I U M A C E T A T E

CH3.CO ONH 4 = 77-o8

Maxinaum Limits of Impuri t ies

Reaction


Ch loride (CI) .

Sulphate (SO4)

Lead (Pb)

Iron (Fe)

pH 6-5 to 7-5

O'Oi pe r ce nt.

0-0005 per cent.

0-005 pe r ce nt,

o-oooi per cent .

0-0003 per cent .

1.

D e s c r i p t i o n .— Co lou r les s hygrosco pic crystals w i th a fa in t odo ur .

2. S o l u b i l i t y .

— R ea di ly soluble in alcohol. Dissolve 5 g. in 50 m l.

of water; a c lear co lour less so lu t ion should be pro duc ed .

3 . R e a c t i o n .

— T he reac tion of a solution of i g . in 20 m l. of car bon

dioxide- f ree w ater shou ld l ie betwe en th e l imi ts of ^ H 6-5 and 7 -5 , us ing

bromothymol b lue or phenol red as ind icator .

4 . N o n - v o l a t i l e M a t t e r .— T o 10 g . add 2 drops of su lphu r ic acid

and ignite gently. N ot mo re th an i mg . of residu e sho uld be left.

5 .

C h l o r i d e .

— D iss olv e 2 g. in 50 m l. of w ate r and ad d i ml. of

dilute nitr ic acid an d i ml. of si lver nitra te solu tion . N o opalesc ence


6 .

S u l p h a t e .

— D isso lve 10 g . in 50 m l . o f water , a dd 2 ml . o f

dilute hydrochloric acid and i ml. of barium chloride solution and al low

to s tand for 6 ho urs . No turb id i ty or precip i ta te shou ld be p rod uc ed .

7 . L e a d .— Dis solv e 12 g. in 30 m l. of hot w ate r, add 5 ml. of d i lute

ammonia so lu t ion and i ml . o f po tass ium cyanide so lu t ion , d i lu te wi th

water to 50 ml . and add 2 drop s of sodium sulph ide so lu t ion . An y bro w n

colour produced should not be deeper than that produced by the addi t ion

of 2 drops of sodium sulphide solution to 50 ml. of an aqueous solution

contain ing 2 g . o f the sample, 5 ml . o f d i lu te ammonia so lu t ion , i ml .

of pota ssium cy anide solution an d i ml. of stan dar d lead solution ( i ml. =

o-o i mg. Pb) .

8 .

Iron .

— Dis solve 5 g. in 45 m l. of w ater , add 5 ml. of d i lute

ammonia so lu t ion and pass hydrogen su lphide through the so lu t ion for

a few seconds. An y colour pro duc ed should not be deep er tha n the

" s tandar d co lours " def ined in append ix 2 .

9 . A s s a y .— D iss olv e 3 g. in 50 m l. of wa ter, add 20 ml. , of ne utra l

formaldehyde so lu t ion and t i t ra te wi th N / j N a O H using p heno lphthale in

as indicator.

I m l . N / i N a O H = 0 -07708 g . CH3 .COONH4

Not less than 96 per cent , should be indicated.


32/319

1 4

A N A L A R S T A N D A R D S

ANALAR

A M M O N I U M B I C A R B O N A T E

NH 4HC O3 = 79-06



Chloride (CI)

Sulphate (SO4)

Heavy Metals CPb)

Iron (Fe)

Tar ry Mat t e r

Arsenic (AS2O3)

per cent .

per cent .

per cent .

per cent .

per cent ,

no reaction

O-O0002 per cent.

(o-2 part per mill ion)

o-oi

0-0002

0-003

0-0003

O OOOI

1. D e s c r i p t i o n .—Colour less crystals or a whi te powder wi th a s l igh t

ammoniaca l odour .

2. S o l u b i l i t y .— D iss ol ve 5 g. in 50 ml . of wa ter. A clear colourless

so lu t ion should be'̂ p roduced .

3 . N o n - v o l a t i l e M a t t e r .— H ea t 10 g . gent ly unt i l the greater par t

i s vo lat i li sed , add 2 dro ps of su lph ur ic acid and igni te gent ly . No t m ore

' than I mg . of resid ue shou ld be left .

4 .

C h l o r i d e .

— Bo il 5 g . wi th 50 ml . o f water un t i l th e volume is

reduced to 5 ml. , add 45 ml. of water, i ml. of di lute nitr ic acid and

I ml . o f s i lver n i t ra te so lu t ion . No opalescence shou ld be prod uce d .

5 . S u l p h a t e .—Boil 5 g . wi th 50 ml . o f water un t i l the volume is

reduced to 5 ml. , add 45 ml. of water, i ml. of di lute hydrochloric acid

and I m l. of ba riu m chlorid e solution and al low to sta nd for i ho ur . No

turb id i ty or precip i ta te should be produced .

6 .

H e a v y M e t a l s a n d I r o n .

—Boil 10 g. with 50 ml. of water unti l

the vo lume is reduc ed to 5 ml . , add 5 ml . o f d i lu te hydroch lor ic acid ,

30 ml . o f water and 10 ml . o f d i lu te ammonia so lu t ion and pass hydrogen

sulphide thro ug h the so lu t ion for a few seconds . A ny colour produce d

should not be deeper than the " s tandard co lours " def ined in appendix 2 .

7 . T a r r y M a t t e r .

— T re at 5 g. wit h 15 ml . of wa ter and 5 g. of c i tr ic

acid and s t i r un t i l d isso lved . No tar ry odour should be perce pt ib le .

8 .

A r s e n i c .

— B oil 10 g . wi th 50 ml . o f water un t i l the volum e is

redu ced to 5 m l . ; ad d 45 ml . o f water and 10 ml . o f s tan nated hyd ro

chlor ic acid and tes t as descr ibed in appendix 4 . An y s tain pro duce d

should not be greater tha n a 0 -002 m g. s tandard s ta in .

9 . A s s a y .— D iss olv e 3 g . in 50 ml . o f N / i HC l . and 50 ml . o f

water and t i t ra te the excess of acid wi th N / i N a O H u sing methyl red as

indicator .

I m l . N / i H C l = 0 -07906 g . NH4HCO3

N ot less tha n 99 per ce nt , and not more than lo i per cent , should be

indicated .


33/319


5

O ' O I

0-25

o-ooi

o-os

o-oi

0-0005

per cent .

per cent .

per cent .

per cent .

per cent .

per cent .

0-00025 per cent .

o-S

per cent .

ANALAR

A M M O N I U M B R O M I D E

N H iB r = 97 -96


Reaction . . . pH not less than 4.5


Chloride (CI)

Brom ate (BrOa) .

Iod ide (I) .

Sul pha te (SO4) .

Heavy Metals (Pb)

Iron (Fe) .

Mois ture

1.


— A whi t e c ry s t a l l i ne powder .

2.

S o l u b i l i t y .

— D iss olv e 5 g. in 50 m l. of wa ter. A clear colourless


3. R e a c t i o n .—The reaction of a solution of i g . in 10 ml. of carbon

dioxide-free water should not be less than pK 4 -5 , us ing brom ocresol

green as indicator.

4 .

N o n - v o l a t i l e M a t t e r .— H ea t 10 g . very gent ly unt i l the greate r

pa rt has volati l ised, add a few dro ps of sulp hur ic acid an d ignite gen tly.

Not more than i mg. of residue should be left .

5.

Ci i lor ide .

—Dissolve 4 g. in 75 ml. of water and 25 ml. of ni tr ic

acid, boil gently and pass a current of halogen free air through the l iquid

unt i l a l l th e l iberated brom ine i s rem ove d. Cool , add 10 m l . o f N / i o AgN Og,

fil ter , was h with wate r and t i tra te the fil trate an d washing s with N / i o

N H4 SC N using ferr ic am mo niu m sulphate as ind icator . N ot less tha n

7-2 ml . o f N / i o N H 4SC N shou ld be r equ i red .

6.

B r o m a t e .

— D iss olv e i g . in 10 m l. of wa ter and add i m l. of di lute

su lphu r ic acid . N o yel low colour should be prod uce d .

7. Iodide .—Dissolve i g . in 10 ml. of water, add 0-05 ml. of ferric

chloride solution and i ml. of starch solution and al low to stand for 10

min utes . No b lue co lour shou ld be produ ced .

8 . Sulphate .—^Dissolve i g . in 50 ml. of water, add i ml. of di lute

hydrochloric acid and i ml. of barium chloride solution and al low to stand

for 6 hou rs . No turb id i ty or precip i ta te should be pr od uc ed .

9 . H e a v y M e t a l s a n d i r o n .—Dissolve 4 g . in 45 ml . o f water , add

5 ml . o f d i lu te ammonia so lu t ion and pass hydrogen su lphide through

the so lu t ion for a few seconds. An y colour prod uce d should no t be dee per


10.

M o i s t u r e .

— D ry 5 g . a t 100° for one hou r . T h e loss in weigh t

should not exceed 25 mg.

(Continued overleaf)


34/319

i6

AMALAR SfANbAftDji

AMMONIUM BROMIDE—continued

I I .

Assay.

—Dissolve 0-4 g. of the dried material from Test No. 9 in

50 ml. of water, add 10 ml. of dilute nitric acid and 50 ml. of N/io AgNOg

and titrate the excess of silver with N/io NH4SCN, using ferric ammonium

sulphate as indicator. Correct the titration for the amount of chloride

found in Test No. 4.

I ml. of N/io AgNOg = 0-009796 g. NH^Br


A N A L A R

AM M ONIUM CARBONATE


Non-volat i le Matter

Chloride

(CI)

Sulphate (SO4)

P h o s p h a t e (P OJ .

Silicate

(SiOj)

Thiocyana te (SCN)

Heavy Metals (Pb)

I ron (Fe)

T a r r y Matter

Arsenic (AsjOs)

(c

O'Oi per cent.

O-0003

per cent.

O'O02 per cent.

o-ooi per cent.

0-0005 Psr cent.

0-001 per cent.

0-0002 per cent.

o-oooi per cent.

no reaction

0-000O2

per cent.

)-2 part per million)

•I . Description.—White powder or translucent crystalline masses with

a strong ammoniacal odour. Consists of an approximately equimolecular

mixture of ammonium bicarbonate, NH4HC0g = 79-06, and ammonium

carbamate, NH2COONH4 = 78-07.

2. Solubility.

—Partially soluble in alcohol. Dissolve 5 g. in 50 m .

of water; a clear colourless solution should be produced.

3. Non-volatile Matter.

—Heat 10 g. gently until the greater

part is volatilised, add 2 drops of sulphuric acid and ignite gently. Not

more than i mg. of residue should be left.

4.

Chloride.

—Boil 5 g. with 50 ml. of water until the volume is

reduced to 5 ml., add 45 ml. of water, i ml. of dilute nitric acid and

I ml. of silver nitrate solution. No opalescence should be produced.

5. Sulphate.

—Boil 5 g. with 50 ml. of water until the volume is

reduced to 5 ml., add 45 ml. of water, i ml. of dilute hydrochloric acid

and I ml. of barium chloride solution and allow to stand for 6 hours.

No turbidity or precipitate should be produced.

6. Phosphate and Silicate.-—Dissolve i g. in 10 ml. of water and

evaporate in a platinum dish until reduced to 1 ml., dilute with 20 ml.


35/319


of water , add i ml . o f d i lu te su lphur ic acid , i ml . o f phosphate reagent

N o . I and i m l . o f pho sph ate rea gent N o . 2 and p lace in a w ate r - ba th at

60° for 10 m inu tes . An y b lue co lour prod uce d shou ld not be deep er tha n

the " standard colour " for si l icate defined in appendix 2.

7 . T h i o c y a n a t e .

— D isso lve 5 g . in 50 ml . o f wa ter an d b oi l u n t i l

the volum e is red uc ed to 10 m l. ; cool, add 10 m l. of di lu te nitr ic ac id,

30 ml . of w ate r and 1 dro p of ferric chlo ride solutio n. N o red or yellow ish-

b rown co lou r shou ld be p roduced .

8 .

H e a v y M e t a l s a n d I r on .

—Boil 10 g. with 50 ml. of water

unt i l the volume is reduced to 5 ml . , add 5 ml . o f d i lu te hydrochlor ic acid ,

30 ml . o f water and 10 ml . o f d i lu te ammonia so lu t ion and pass hydrogen

sulphide thro ugh the so lu t ion for a few secon ds. An y colour pro duc ed

shou ld no t be deep er tha n th e " s t andard co lo u r s" defined in ap

pend ix 2 .

9 . T a r r y M a t t e r .—Treat 5 g. with 15 ml. of water and 7 g. of ci tr ic

acid and s t i r un t i l d isso lved . N o tar ry odo ur should be per cep t ib le .

10 . A r s e n i c .— B oil 10 g . wi th 50 ml . o f wa ter un t i l the volume is

reduced to 5 m l . , add 45 ml . of wa ter , 10 ml . of s tann ated hydro chlor ic

acid and tes t as descr ibed in app endix 4 . Any s tain pro duc ed shou ld

not be greater than a 0 -002 mg. s tandard s ta in .

11. A s s a y .

— D isso lve 2 g . in 50 m l . o f N / i H C l an d 50 m l . o f

water and t i t ra te the excess of acid w i th N / i N a O H using meth yl red as

indicator .

I m l . N / i H C l = 0-01703 g. NH3

Not less than 31 per cent , o f NH3 should be ind icated , equivalen t to

9 5 -3 p e r c e n t, o f N H 4 H C O 3 . N H 2 C O O N H 4 .

A N A LA R

A M M O N I U M C H L O R I D E

NH4CI = 53-50


Reaction

Non-volati le Matte:

Sulphate (SO4)

Nitrate (NO3)

Phosphate (PO4)

Thiocyanate (SCN)

Heavy Metals ' (Pb)

Iron (Fe)

Tar ry Mat t e r

Arsenic (AsjOa)

pn not less than 4-5

o-oi per cent .

o-oi per cent .

0-00005 psr cent.

o-ooi per cent .

o-ooi per cen t .

0-0004 ps r cen t .

o-oooa pe r ce nt.

no reaction

o-cooi per cent ,

( i part per mill ion)

(Continued o verleaf )


36/319

l 8 ANALAR STANDARDS

AMMONIUM

CHLORIDE—continued

1.

Description.

—A white crystalline powder.

2.

Solubility.

— D issolv e 5 g. in 50 ml. of water. A clear colourless

solution should be produced.

3.

Reaction.—The reaction of a solution of i g. in 10 ml. of carbon

dioxide-free water should not be less than pH 4-5, using bromocresol

green as indicator.

4.

Non-volati le Matter.

—Heat 10 g. gently until the greater part

is volatilised, add 2 drops of sulp huric acid and ignite gently. No t more

than I mg. of residue should be left.

5. Sulphate.—Dissolve 5 g. in 50 ml. of water, add

.1

ml. of dilute

hydrochloric acid and i ml. of barium chloride solution and allow to stand

for 6 hou rs. No turbidity or precipitate should be prod uced .

6. Nitrate.—Dissolve o-i g. in i ml. of N/io HCl and add 4 ml.

of diphenylbenz idine reagent. Any blue colour produ ced should not be

greater than that produced by adding 4 ml. of the reagent to r ml. of

N/ io HCl .

7. Phosphate.—Dissolve i g. in 20 ml. of water, add 3 ml. of dilute

sulphuric acid', i ml. of phosphate reagent No. i and i ml. of phosphate

reagent N o. 2 and place in a wa ter- bath at 60° for 10 minute s. Any blue

colour produced should not be deeper than the " standard colour " defined

in appendix 2.

8 . Thiocyanate.— Dissolve 5 g. in 40 ml. of water and m ix with

0-5 ml. of cupric sulpha te solution and o- i m l. of py ridi ne; then add

5 ml. of chloroform, shake vigorously in a separating funnel and allow to

separa te. D raw off the lower layer, shake it with 2 ml. of water and again

allow to separate. T he chloroformic layer should not be coloured yellow

or green.

9 . Heavy Metals and Iron.—Dissolve 5 g. in 45 ml. of water, add

5 ml. of dilute ammonia solution and pass hydrogen sulphide through the

solution for a few seconds. Any colour produced should not be deeper

than the " standard colours " defined in appendix 2.

10.

Tarry Matter.—Moisten 2 g. with i ml. of nitric acid and dry in a

porcelain dish on a wa ter-b ath. T he residue should be perfectly w hite.

r i . Arsenic.— Dis solve 5 g. in 5

analar standard

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