266 - Sulphuric Acid
266 - Sulphuric Acid
266 - Sulphuric Acid
( Reaffirmed 2003 )
Indian Standard
SULPHURIC ACID - SPECIFICATION
(Third Revision)
UDC 661.25
0 BIS 1993
BUREAU
OF INDIAN
MANAKBHAVAN,
NEW DELHI
my
1993
STANDARDS
9 BAHADUR SHAHZAFARMARG
110002
Price Group 7
CHD 002
FOREWORD
This Indian Standard ( Third Revision ) was adopted by the Bureau of Indian Standards, after the draft
finahzed by the Acids, Alkalis and Halides Sectional Committee had been approved by the Chemical
Division Council.
This standard was first published in 1950 and then revised in 1961. The second revision was brought out
in 1977 whetem the pure grade was substituted by chemically pure grade. Changes were also made in
various requirements,
namely, total acidity, iron, chlorides, lead, arsenic, oxidizable impurities and
ammonia for both chemically pure as well as analytical reagent grades of sulphuric acid. In the second
revision, the specific gravity requirement was deleted as it was felt that this requirement need not be a
part of the specification. However, reference may be made to IS 4048 : 1989 Density composition
tables for aqueous solutions of sulphuric acid (first revision ) for correlation between density and
composition of sulphuric acid.
In this revision, the requirements for iron content for the battery grade acid, oxidizable impurities
the analytical reagent grade, antimony and platinum have been suitably amended. The method
determination of oxidizable impurities has been modified. Suitable changes have been made in
packing clause. This revision also incorporates
Amendments No. 1, 2 and 3, issued in 1981, 1984
1986 respectively.
for
for
the
and
For general information regarding precautions to be observed in safe handling and use of sulphuric acid,
reference may be made to IS 4262 : 1967 Code of safety for sulphuric acid.
In the preparation of this standard, reference has been made to the following standards published by the
International Organization for Standardization ( IS0 ) :
of
ISO/910-1977
Sulphuric acid and oleum for industrial use - Determination
calculation of free sulphur trioxide content of oleum, titrimetric method.
ISO/913-1977 Sulphuric acid and oleum for industrial use - Determination
of
method.
ISO/R 915-1968 Sulphuric acid and oleum for industrial use - Determination
2, 2-bipyridyl spectrophotometric
method.
ISO/2717-1973
Sulphuric acid and oleum for industrial use - Determination
Dithizone photometric method.
total
ash -
acidity
and
Gravimetric
For the purpose of deciding whether a particular requirement of this standard is complied with, the
final value, observed or calculated, expressing the result of a test or analysis, shall be rounded off
in accordance with IS 2 : 1960 Rules for rounding off numerical values ( revised ) . The number of
significant places retained in the rounded off value should be the same as that of the specified value in
this standard.
IS 266 : 1993
Indian Standard
2 REFERENCES
2.1 The Indian Standards listed
necessary adjuncts to this standard:
below
are
IS No.
Title
264 : 1976
265 : 1993
1070 : 1992
revision )
revision )
1388 : 1959
2088 : 1983
4905 : 1968
5296 : 1979
Reagents bottles
Methods for determination
of arsenic (seco& revision)
Methods for random sampling
pure
Chloroform,
and
technical (Jil:rt revision)
Analytical Reagent
3 GRADES
Subject to agreement
purchaser and the supplier,
concentrated
acid complying
requirements given in co1 4 of
that for total acidity, may also
more dilute or more concentrated
Pure and
Technical (Tech),
Battery,
Chemically pure (CP), and
Analytical reagent (AR).
between
the
battery
grade
with all the
Table 1 except
be supplied as
acid.
4.3.2.2 Subject
to agreement
between
the
purchaser and the supplier, requirements
for
battery grade acid (concentrated
and drlute)
may include, in addition to the requirements
given in Table 1, limits for antimony and
platinum as follows:
4.1 Description
4.1.1 Technical Grade
Sulphuric acid of technical grade shall be a
liquid not darker than brown in colour.
Table 1 Requirements
ii>
Characteristic
ii)
h)
percent
by mass, Max
iii)
iv)
Chlorides
v)
vi)
vii)
viii)
ix)
Oxidizable
Max
(4)
(5)
980
950
300
(8)
98 0
A-2
002
001
0002
A-3
005
0003
0001
0001
0000 05
(05 ppm)
A-4
0%01
0000 3
(3 ppm)
0003 5
0.000 02
(02 ppm)
A-5
0002
0000 1
(1 ppm)
A-6
00002
(2 ppnl)
0000 005
(0 05 ppni)
A-7
0 000 4
(4 I-wn~
A-U
0005
(I 7 ppni)
0000 12
0000 04
(04 ppm)
00
rJ.O?
0004
by mass,
by mass, Max
980
17)
006
Organic matter
Nitrates
(6)
Analyttcal
Reagent Grade
Method of Test,
I Ref to Cl No.
in Annex A )
02
by mass, fiflox
by mass, Max
impurities
Requirement
h--------_-__-__~
(,hemically
Battery Grade
r__c_-&i_.-_~
Pure Grade
Concentrated
Dilute
(3)
(2)
(1)
i)
~---------------Technical
Grade
E
..
0 001
0000 02.
A-9
A-IO
(02 ppm)
x)
xi)
by mass, Max
000
0000 2
(2 ppm)
0 000 6
A-11
,I-12
(6 ppm)
xii)
M;lngalle\e
xiii)
xiv)
XV)
g;w;tc;a2trites
by mass, Max
by mass, Max
by mass, Max
and ammonia
by
0 000 I
(I ppm)
0.000 03
(03 ppm)
0003
0001
0003
0001
<\-IS
0 003
0001
000 3
A-16
A-l?
A-l-l
c
U
s
IS 266 : 1993
fiiled with the same material to prevent movement. Carboys shall be packed in suitable iron
hampers or wooden crates, with the inter-space
being sufficiently stuffed with whiting, keiselguhr
or other noncombustiblemateria1.
6 SAMPLING
The method of drawing representative samples
of the material shall be as prescribed
in
Annex B.
ANNEX
QUALITY
A-2.1.1
A-2 DETERMINATION
Lunge-Rey Pipette
Lunge-Rey
dimensions
available, a
of the type
OF TOTAL
ACID
A-2.1 Apparatus
OF RtiAGENlS
A-l.1
do not contain
analysis.
A-2.2 Reagents
A-2.2.1 Standard Sodium Hvdroxide Solution,
1 N, freshly srandardized.
_
A-2.2.2 Methyl Red Indicator
Dissolve 1 g of methyl red in 95 percent (V/Y)
ethanol and dilute to 100 ml with the same
ethanol.
ACIDITY
A-2.0 General
The material
is titrated
against standard
solution of sodium hydroxide using methyl red
as indicator.
3
IS 266 : 1993
A-2.3 Procedure
2mm BORE
II6
/
B5
in millimetres.
LUNGB-RBYPIP~B
All dimensions
than
Higher
t
!2
Ao.
Cmfent
60mm
Equal to or Lower
FIG.
SPHBRSCAL
GLASS
hydroxide
titration,
ANIPOULS
in ml of
solution
c X N X 4.904
it/l
standard
used
sodium
for
the
IS 266
OF
RESIDUE
Dissolve 10 g of hydroxylammonium
chloride
(NH, OH HCI) in water and dilute to 100 ml.
A-4.1.2.3 Ammonium acetate solution, 30 percent
(m/r).
A-4.1.2.4 22 -Bipyridyl solution
ON
A-3.1 Procedure
Weigh to the nearest 10 mg about 50 g of the
sample in a platinum or silica dish of lOO-ml
capacity,
previously ignited at 800 -& 5OC,
cooled in a desiccator and weighed. Evaporate
the acid carefully on a sand-bath, heating the
dish containing the test portion. Heat to dryness. Place the dish containing the residue in an
electric furnace heated at 800 f 50C and keep
at this temperature
for about 15 minutes.
Remove the dish from the furnace, cool in a
desiccator and weigh. Repeat heating, cooling
and weighing till constant mass is obtained.
Dissolve
M, x 100
Ma
A-4.1.3.1
Standard Iron
Solution B
ml
0 (compensation
solution)
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
45.0
50-O
OF IRON
Corresponding to Fe
Pg
0
50
100
150
200
250
300
350
400
450
500
Photometer
Any spectrophotometer
suitable for measurement at a wavelength of about 522 nm or
photoelectric calorimeter.
A-4.1.2 Reagents
f-$.2.1
.
where
A-4.1.1.1
in 10 ml of dilute
acid and dilute to 100 ml.
A-3.2 Calculation
A-4 DETERMINATlON
1 g of 2,2 -bipyridyl
hydrochloric
:1993
5
.
Is 266 : 1993
m x 100 x 100
VxM
where
m =
A-4.2.1 Apparatus
A-4.2.1.1
A-4.2.2 Reagents
A-4.2.2.1
Hydrochloric
acid, 1 : 1 (v/v).
iron
solution B,
Same
as
A-4.2.3 Procedure
A-4.2.3.1
in the
V =; volume
test.
A-4.2 Metbod B ( Thiocysnate Method )
A-4.2.0 General
The colour produced by a known quantity of
the material with ammonium thiocyanate is
compared with a control containing known
quantity of iron.
Accurately
weigh 50 g of the sample in a
platinum or silica dish (loo-ml capacity). Place
on a sand-bath and carefully evaporate to dryness. Cool, add 2 ml of hydrochloric acid and
25 ml of water and heat to facilitate dissolution.
Cool and carry out the test with this solution as
prescribed in A-4.2.3.1, but using 2.5 ml of
standard iron solution B in the control test.
A-4.2.3.4 The limit prescribed for the nppropriate grade in Table 1 shall be taken as not
having been exceeded if the intensity of colour
produced in the test with the material is not
greater than that produced
in the respective
control test.
IS 266 : 1993
4 N.
approximately
grade dilute
,
c) 7 ml in the case of CP grade acid, and
OF LEAD
A-6.0 General
After evaporation of a test portion, lead is
reduced by hydroxylammonium
chloride. Complexes are formed of interfering elements with
ammonium citrate and potassium cyanide. Lead
is extracted at pH between 8.5 and IO by a
solution of dithizone in chloroform. Excess of
dithizone is eliminated by an ammoniacal solution of potassium cyanide. Lead dithizonate is
determined by photometric
measurement
in
chloroform solution at a wavelength of about
520 nm.
A-6.1 Range
This method is applicable for the determination
of lead (as Pb) contents greater than 1 mg/kg.
A-6.2 Apparatus
A-6.2.1 Spectrophotometer
Any spectrophotometer
suitable for measurement at a wavelength of about 520 nm or
photoelectric
absorptiomcter fitted with filters
giving maximum transmission between 500 and
540 nm.
A-6.3 Reagents
A-6.3.1 Chloroform, see 1s 5296 : 1979.
A-6.3.2 Hydrochloric Acid, approximately
12 N
(see IS 265 : 1993).
A.6.3.3 Ammonium Citrate Solution, 10 percent
(m, v).
A-6.3.3.1 Purification of the solution
To 100 ml of solution, add ammonia solution,
approximately 0.91 g/ml, until the pH reaches
a value between 8.5 and 10, checking with the
indicator paper. Transfer the solution to a
separating funnel, add 10 ml of the dithizone
solution
and shake vigorously.
Allow to
separate, withdraw and reject the organic phase.
Repeat the extraction, each time with 5 ml of
the dithizone
solution.
until green colour
Allow to separate, withdraw and
remains.
reject the organic phase.
A-6.3.4 Potassium Cyanide Solution, 50 g/l.
f6$;.:
Hydroxylammonium
Chloride Solution,
.
A-6.3.6 Ammonia Solution, approximately
5 N.
IS 266 : 1993
precipitate
to settle, filter through a sintered
glass crucible and wash with water until there
is no further acid reaction. Dry the precipitate
in a desiccator containing
concentrated
sulphuric acid under vacuum and in darkness, for
3 to 4 days. Grind the solid dry product quickly
and transfer immediately to a small dark glass
bottle. The dith zone, thus purified and stored
away from direct sunlight, can be kept for at
least 6 months.
l-cm cell
Cyanide
Solution,
Tnto eleven separating funnels of IOO-ml capacity, fitted with ground glass stoppers, transfer
IO ml of water and add respectively the volumes
measured with the burette, of the standard lead
solution B indicated below:
Standard Lead
Solution B
g/l
ml
0 ( compensation
solution )
1-o
2-o
3.0
4.0
5.0
6.0
7.0
8.0
9.0
10.0
CAUTION
precautions.
In particular,
do not add acids to
solutions
containing
cwnides,
otherwise hydrogen
cyanide will be released.
Corresponding
Mass of Lead
clg
0
10
20
30
40
50
60
70
80
90
100
IS 266 : 1993
where
sensitive to
be protected
A-7 DETERMINATION
A-7.1 Procedure
OF ARSENIC
A-8.1.1 Potassium
exactly 0.01 N.
Permangariate
Solution,
A-8.2 Procedure
Take a known volume of the material ( say 10 to
20 ml ) in a 250-ml conical flask and dilute with
an equal volume of water. Titrate the solution
against standard potassium permanganate to a
light, permanent pink colour end pomt.
A-8.3 Calculation
Oxidizable impurities ( as SO, )
,GxVxzv
percent by mass
where
V = volume in ml of standard permanganate solution used for the titration,
N = normality of potassium permanganate
solution, and
M = mass in g ( volume x relating density)
of the sample taken for the test.
A-6.4.5 Calculation
By means of the
calibration
curve ( see
A-6.4.3.4 ), determine the quantity of lead
corresponding to the values of the photometric
measurements:
(M, -M,)
x D
Lead ( as Pb ), ppm = --lF--
( see
Is 266 : 1993
A-10.1.2 Diphenylamine Solution
A-12.1.3
A-10.2 ProcFdure
Dilute 6 ml of the material with 2 ml of water,
cool to 60-C and add one drop of concentrated
hydrochloric
acid and 1 ml of diphenylamine
solution.
A-10.2.1 The limit prescribed in Table 1 shall
be taken as not having been exceeded if no blue
colour is produced.
A-11 TEST FOR AMMONIA
A-11.1 Reagents
A-11.1.1
Sodium
Hydroxide
Solution,
appro-
ximately 30 percent.
A-11.1.2 Nessler Solution
Dissolve 10 g of potassium iodide in 10 ml of
wa\er and add to it slowly, with stirring, a
saturated aqueous solution of mercuric chloride
until a slight permanent precipitate forms. Add
30 g of potassium hydroxide and, when it has
dissolved, add 1 ml more of mercuric chloride
solution and dilute to 200 ml with water. Allow
to settle overnight and then decant the clear
solution. Keep the solution in a bottle closed
with a well-fitting rubber stopper.
A-11.1.3 Standard Ammonium Chloride Solution
Dissolve O-314 g of ammonium chloride in one
litre of water. Further dilute 100 ml of the
sdlution to 1 000 ml. One millilitre of the diluted
contains
0.01 mg of ammonia
solution
( as NH8 ).
A-11.2 Procedure
Add exactly 20 g of the material to 40 ml of
water, cool in ice and make alkaline with
sodium hydroxide solution. Add to the mixture
1 ml of Nessler solution. Carry out a control
test usirig 4 ml of standard ammonium chloride
solution in place of the material, finally diluting
the contents to the same volume as in the test
with the material.
A-11.2.1 The limit prescribed in Table 1 shall
be taken as not having been exceeded if the
intensity of colour produced in the test solution
is not greater than that produced in the control
test.
A-12 TEST FOR SELENIUM
A-12.1 Reagents
A-12.1.1 Concentrated Hydrochloric Acid JS 265 : 1993.
( see
Concentrated
Nitric
Acid -- ( see
IS 264 : 1976 ).
A-13.1.2 Potassfum Periodate
A-13.1.3 Standard
Potassium
Solution, exactly O*OO
1 N.
Permanganate
A-13.2 Procedure
A-13.2.1 For Battery Grade Concentrated Acid
IS 266 : 1993
equal volume of a solution containing 2.3 ml of
standard potassium permanganate solution, 5 ml
of nitric acid and 0.5 g of potassium periodate
in water, this solution having been treated in
the same manner.
A-13.2.1.1 The relevant
limit prescribed in
Table 1 shall be taken as not having been
exceeded if the intensity of colour produced by
the material is not greater than that produced
in the control test.
A-13.2.2 For Battery Grade Dilute Acid
Carry out the test as described under A-13.2.1
using exactly 25 g of the material for test and
0.7 ml of standard potassium permanganate
solution for [he control test.
A-14 TEST FOR COPPER
The test shall be carried out only if the
on ignition as obtained under A-3.1
0.003 percent in case of battery grade
trated acid and O*OOlpercent in case of
,grade dilute acid.
residue
exceeds
concenbattery
Hydroxide,
Acid -
relative
( see
den-
sity 0.90.
A-14.2.3
Dissolve
in 1 000
solution
A-15.2.5 Ammonium
solution ( m/v ).
Thiocyanate,
A-15.2.8
Acid,
den-
percent
relative
density
Ferrocyanide
Solution, 5 per-
&solve
O-1 g of pure zinc in IO ml of hydrochloric acid and dilute to 1 000 ml. One
mthihtre of this solution contains 0.1 mg of
zinc.
A-15.2.9 Calcium Carbonate
A-15.3 Procedure
relative
zinc-
A-14.3 Procedure
if the residue
A-3.1 exceeds
grade concencase of battery
A-15.1 Apparatus
A-15.2.7 Potassium
cent ( m/v ).
50-ml capacity.
A-14.2 Reagents
Ammonium
A-15.2.6 Hydrochloric
I *20.
A-14.1 Apparatus
A-14.2.2
A-15.0 General
A-15.2.3 Ammonium
sity O-90.
A-14.0 General
I6 266 : 1993
of standards covering the range in which the
sample falls has been prepared by measuring
portions of the standard zinc solution into
lOO-ml Nessler cylinders. Dilute the standard
and sample solutions to about 90 ml and add
3 ml of hydrochloric
acid to the standard
solution and 2 ml of potassium ferrocyanide
solution to all solutions. Dilute the contents of
each Nessler cylinder to the mark and mix
thoroughly. After standing for at least 5 minutes
compare the turbidity of the standard and the
sample. Calculate the percentage of zinc from
the quantity of sample taken and the standard
solution similar in turbidity to that of the
sample.
A-17.1 Reagents
NITRITES
grade
the respective
control
test.
AND
A-17.1.3
( v/v )-
Dilute
A-17.1.4
A-17.1.5
A-16.2 Reagents
Solution,
approxi-
Acid,
Ammonium
Hydroxide,
1:4
Dissolve 0.548 g of antimony potassium tartarate in water and make up to 1 000 m!. Dilute
100 ml of this solution to 1000 ml. One millilitre
of this solution contains O-02 mg of antimony
( as Sb ).
A-17.1.6 Sodium Sulphite
A-16.2.3 Dilute
mately 6 N.
dilute
A-16.1 Apparatus
of
A-17.1.7 Concentrated
IS 265 : 1993.
Hydrochloric
Acid,
See
A-17.2 Procedure
A-17.2.1 For Battery Grade Concentrated Acid
approxi-
A-17.2.1.1
Preliminary test
IS 266 : 1993
without first removing arsenic. In this case,
evaporate
exactly 20 g of the material to
4 or 5 ml, proceed as for the determination
of arsenic by modified Gutzeit method
as
prescribed
in IS 2088 : 1983 except that
the solution
is finally warmed to about
60C and kept at that temperature
for one
hour. Developed
the colour by immersing
the mercuric chloride
test paper strip ,in
dilute
ammonium
hydroxide.
Compare
the stain with that obtained
under identical conditions
from a solution containing
4 ml of concentrated
sulphuric
acid and
1 ml of standard antimony
solution.
b) If the arsenic content ( as As ) has been
found to exceed O*OOO012 percent by mass,
the arsenic present may interfere with the
determination
of antimony
and shall first
be removed.
In this case, evaporate
exactly 100 g of the material
to 4 or 5 ml
in a 250-ml beaker,
cool and cautiously
add
10 ml of water containing
about
0.25 g of sodium sulphite. .Evaporate
until
fumes
begin to appear,
cool and add
100 ml of concentrated
hvdrochloric
acid.
Boil slowly in an open beaker until the
volume is reduced to 40 or 45 ml, keeping
the temperature
of the liquid below 110C.
Use boiling tubes or some other device
to minimize
bumping,
and take care not
to let the volume
get too small or the
temperature
too high, otherwise
some of
the antimony
may be lost. Transfer
to a
50-ml volumetric
flask and dilute
to
50-ml.
To a 10 ml aliquot,
add 10 ml of
water and 3 ml of concentrated
sulphuric
acid. Dilute
to 50 ml and proceed
as
directed in A-17.2.1.2 (a), comparing
the
stain with that obtained under identical
conditions
from
a solution
containing
1 ml of standard antimotiy
solution,
3 ml
of concentrated
sulphuric
acid and 4 ml
of concentrated
hydrochloric
acid.
A-17.2.2
~-17.2.2.1
Actual rest
Reagents
Aqua Regia
Prepared
by mixing three volumes of concentrated
hydrochloric
acid with one volume of
concentrated
nitric acid.
A-18.2 Procedure
A-18.2.1
Acid
Evaporate
10 ml of the material
in a small
porcelain
evaporating
dish on a sand-bath.
E,vaporate completely
but do not heat the residue
unnecessarily.
Cool and add 2 ml of aqua regia.
Cover the dish with a watch-glass
and digest on
the steam-bath
for 10 minutes.
Remove
the
watch-glass
and evaporate
the solution
to five
or six drops. If the solution accidentally
evaporates
completely,
repeat
the treatment
with
aqua regia. Absorb the residual solution
in a
piece of thin asbestos
paper not more than
O-8 mm thick, 5 mm wide and 30mm long. Hold
the paper in a crucible tongs and dip half of it
into the solution. Dry gently over a flame and
repeat until all of the solution
is absorbed.
Dry
the paper and ignite to redness in a moderate
Bunsen flame ( 8 to 10 cm high with good air
mixture ). Momentarily
shut off the gas and
then turn it on again so that the stream of
unignited
gas plays on the hot asbestos paper,
held vertically.
The limit prescribed
in 4.3.2.2
(b) shall be taken as not having been exceeded
if there is no glowing of the paper.
A-18.2.2
FOR PLATINUM
L._,.___ E,,~
. _../.,,
^.,._
-xL--
IS 266 : 1993
ANNEX B
( Clause 6.1 )
SAMPLING
B-l
GENERAL
REQUIREMENTS
OF SULPHURIC
The representative
samples so drawn
constitute individual test samples.
OF
SAMPLING
B-1.0 In drawing samples, the following precautions and directions shall be observed.
Precautions shall be taken to protect
being sampled,
samples, the material
sampling instrument and the containers
samples from adventitious contamination.
B-l.1
ACID
Table 2
the
the
for
Number of Containers
for Sampling
to be Selected
( Clause B-2.2 )
No. of Containers to be
Lot Size
Selected
B-l.2
To draw a representative
sample, the
contents of each container
shall be mixed
thoroughly by rolling, shaking or stirring by
suitable means and with necessary caution.
(1)
(2)
up te
1s
16 ,, 25
26,, 50
3
4
51 ,, 100
101 ,, 300
301 ,, 500
501 ), 800
801 ,, 1 000
1 001 and above
6
7
8
Y
10
B-2.1 Lot
_..-
3
9 20 TOL3
i
350
TO
750
14
shall
SAMPLIKG INSTRUMENT
IS 266 : 1993
~-3.1.1 A composite sample shall be prepared
by mixing thoroughly a small but approximately
equal quantity from each of these individual
samples. The quantity of material for the
composite sample shall be as given in B-4.1
and B-4.2.
. three
on each of
given in
composite
Date of Issue
BUREAU
OF
INDIAN
Text Affected
STANDARDS
Headquarters:
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$2
-i-T.~~-_-IIC*_..l_.-~.~--
--
AMENDMENT
1 FEBRUARY 2003
TO
SULPHURIC ACID SPECIFICATION
IS 266:1993
N().
(Third Revision )
the following at the appropriate
( /a,qc 1, C/C~USC
2.] ) lnser(
determination
place:
of traces of heavy
I Pt[qc 2, S1 No, Table 1. (ii). {iii) and (v) ] Substitute the following for
the ex]s[inz:
Mdlxt(f
SI
(lxw+cteristic
Requirement
No.
T@(lMto
C&et%
...*.
,
\
in.hm
Technical
Grade
11)
Residue
on
BaItcry Grade
Concentrated
Dilute
A)
ChemicAnalytical
ally Pure Reagent
Grade
Grade
0.05
0.06
0.02
0.02
0.002
A-3
0.01
0.003
0.001
0.001
0.00005
A-4
0.005
0.002
0.00 I
A-61
1s 7017
v)
Hwy
(as
metals
lead),
by
pcrcerrt
moss, Max
( Page 3, clause 5.1.5, seconcf sentence ) Substitute the following for the
existing:
5.1.6 [n case of dilute sulphuric acid of relative density not more than 1.216,
certified in writing by the consignor, the inside packing of the case may be straw
or gr;iss or wood shavings or the packing may be thermocol and the mass of each
c:ise shul I not exceed 130 kg.
1
A-6.1 )
OF HEAVY METAL
A-6.O GENERAL
Two methods
A-6.1 Method B
Evaporate 11 cc acid to dryness, Add 2 ml dilute hydrochloric acid and 18 ml
water. Warm to facilitate dissolution. To this add 30 ml water and 10 ml dilute
ammonia solution ( 5N ). Pass hydrogen sulphide gas to the solution for a few
seconds. The colour of the solution thus obtained is compared with a solution
containing 2 ml standard lead solution ( 1 ml = 0.01 m: Pb) and 3 ml dilute acetic
acid (5 N). Add 10 ml of dilute ammonia solution and made up to 50 m} volume
with water through which hydrogen sulphide gas is passed for few seconds. The
material shall deemed to have passed the test if the colour of the sample solution
is Iighter than standard solution.
( Page 9, clause A-7.1 ) Substitute the following for the existing:
A-7.1 Procedure
To 22 ml acid add
residue cautiously
Add to the cooled
(1.5 M) and test as
( Page 9, clause
A-8.2 Procedure
Take a known volume of the material (say 10 to 20 ml) in a 250-ml conical flask
and dilute the acid with 5 times its volume of water with continuous cooling in
ice. Titrate the solution against standard potassium permanganate to a iight,
permanent pink colour end point.
(CHD1)
Reprography Unit. 131S,New Ilelhi, India
2