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है”ह”ह
IS 247 (1987): Sodium sulphite, anhydrous [CHD 1: InorganicChemicals]
Indian Standard
IS : 247 - 1987 (Reaffirmed 2010)
SPECIFICATION FOR SODIUM SULPHITE, ANHYDROUS
(Fourth Revision) Second Reprint JULY 2007 (Including Amendment No. 1)
UDC 661.833.522
© Copyright 1987 B U R E A U O F I N D I A N S T A N D A R D S MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG
NEW DELHI 110002
Gr 5 November 1987
AMENDMENT NO. 1 NOVEMBER 2004 TO
IS 247 : 1987 SPECIFICATION FOR SODIUM SULPHITE, ANHYDROUS
( Fourth Revision )
( Page 6, clause A-2 ) — Substitute the following for the existing clause:
A-2 DETERMINATION OF SODIUM SULPHITE
A-2.0 Outline of the Method — This method is used to determine the purity of sodium sulphite in the presence of sodium bisulphite. This is done in two stages. In the first stage, sodium bisulphite is determined by titration with sodium hydoxide using phenolphthalein as indicator. In this titration, sodium bisulphite is converted into sodium sulphite. This is then titrated with standard hydrochloric acid using methyl orange as indicator. The difference of the two readings gives a measure of sulphite. The above chemical reactions are given by the following equation:
NaHSO3 + NaOH = Na2SO3 + H2O
Na2SO3 + HCl = NaHSO3 + NaCl
A-2.1 Reagent
A-2.1.1 Standard Sodium Hydroxide Solution — 0.1 N.
A-2.1.2 Phenolphthalein Indicator
A-2.1.3 Standard Hydrochloric Acid Solution — 0.1 N.
A-2.1.4 Methyl Orange Indicator
A-2.2 Procedure — Weigh accurately about 0.55 g of the material and dissolve it in about 50 ml of water. First titrate with standard sodium hydroxide solution using phenolphthalein as indicator. Then titrate with standard hydrochloric acid using methyl orange as indicator.
1
Amend No. 1 to IS 247 : 1987
A-2.3 Calculation
a) Sodium bisulphite (NaHSO3) content, percent by mass =
where
V1 = volume in ml of standard sodium hydroxide solution used in first titration,
N1 = normality of standard sodium hydroxide solution, and
M = mass in g of the material taken for the test.
b) Sodium sulphite and bisulphite (Na2SO3 and NaHSO3) content, percent by mass =
where
V2 = volume in ml of standard hydrochloric acid solution used in second titration,
N2 = normality of standard hydrochloric acid solution, and
M = mass in g of the material taken for the test.
c) Sodium sulphite (Na2SO3) content, percent by mass = b - a
( CHD 1 )
2
IS : 247 - 1987
Indian Standard SPECIFICATION FOR
SODIUM SULPHITE, ANHYDROUS
(Fourth Revision)
Inorganic Chemicals ( Misc ) Sectional Committee, CDC 3
Chairman DR M. S . VAIDYA
Members SHRI R. S. V Y A S ( Alternate to
Dr M. S. Vaidya ) DR A. N. BHAT
DR B. S. M O U L I K ( Alternate ) DR R. M. BHATNAGAR S H R I R. C. BHATTACHARYA
Representing Dharamsi Morarji Chemical Co Ltd, Bombay
Hindustan Lever Ltd, Bombay
Projects & Development India Ltd, Sindri Directorate General of Technical Development,
New Delhi SHRI K U L T A R SINGH ( Alternate )
S H R I S. N. BHATTACHARYA Tata Chemicals Ltd, Bombay S H R I S. G A N A P A T H Y ( Alternate )
S H R I J . C. BOSE S H R I A. K. D A S ( Alternate )
CONTROLLER GENERAL SHRI V. K. J A I N ( Alternate )
SHRI S. D A S S H R I YUDHISTHIR ( Alternate )
D R A. V. D E O S H R I C. H. PAGE ( Alternate )
D R S . G H O S H
DR S . H. IQBAL S H R I V. B. K H A N N A
Indian Oxygen Ltd, Culcutta
Indian Bureau of Mines, Dhanbad
Geological Survey of India, Calcutta
Associated Cement Companies Ltd, Bombay
In personal capacity ( 17-A, 'F' Block, Saket, Malviya Nagar Extension, New Delhi )
National Chemical Laboratory ( CSIR ), Pune Directorate General of Supplies & Disposals,
New Delhi S H R I N. K. K A V S H A L ( Alternate )
S H R I N . J . K I K A N I Sarabhai M. Chemicals, Vadodara S H R I H. H. KAVARANA ( Alternate )
S H R I P . R . M A L H A N Development Commissioner, Small Scale Industries, New Delhi
S H R I R. M U K H O P A D H Y A Y ( Alternate )
( Continued on page 2 )
1
© Copyright 1987 BUREAU OF INDIAN STANDARDS
This publication is protected under the Indian Copyright Act ( XIV of 1957 ) and reproduction in whole or in part by any means except with written permission of the publisher shall be deemed to be an infringement of copyright under the said Act.
IS : 247 - 1987
( Continued from page 1 )
Members D R A N I L PANDIT
Representing Deepak Nitrite Ltd, Vadodara
S H R I C. S. NAGAR ( Alternate ) DR P. G. PRADHAN
S H R I T. S. KALAHASTY S H R I A. K. R A O
Golden Chemicals Pvt Ltd, Bombay ( Alternate )
Shriram Foods & Fertiliser Industries, New Delhi SHRI A. K. M E H R A ( Alternate )
D R S. B. R A Y SHRI P. D A S ( Alternate )
S H R I B. K. SACHAR
Ministry of Defence ( DGI )
Ministry o f Defence ( R & D ) SHRI A. D. G U P T A ( Alternate )
S H R I C. R. SANTHANAKRISHNAN Travancore Chemical & Mfg Co Ltd, Mettur Dam S H R I K. V. M A N I ( Alternate )
S H R I C. P. SHARDA SHRI L. B. SRIVASTAVA
D R V . S . SUBRAMANIAN
Shri Ram Institute for Industrial Research, Delhi ( Alternate )
Regional Research Laboratory ( CSIR ), Hyderabad D R M O H D ZAFAR J A M I L ( Alternate )
S H R I N. C . T H A K K A R
S H R I S. C. T H A K U R
Indian Chemical Manufacturers' Association, Calcutta
Indian Oil Corporation Ltd ( Refineries & Pipelines Division ), New Delhi
S H R I M U S A F I R SINGH ( Alternate ) SHRI SATISA CHANDER,
Director ( Chem ) Director General, BIS ( Ex-officio Member )
Secretary S H R I M. BAKSHI G U P T A
Deputy Director ( Chem ), ISI
A u x i l i a r y C h e m i c a l s S u b c o m m i t t e e , C D C 3 : 1 8
Convener S H R I J . C. BOSE
Members S H R I S. BALASUBRAMANIAN
S H R I K. SUBRAMANIAN DR R. M. BHATNAGAR S H R I A. T. BRAHMBHATT
Indian Oxygen Ltd, Calcutta
Tamil Nadu Chemical Products Ltd, Madras ( Alternate )
Projects & Development India Ltd, Sindri Kalali Chemicals Ltd, Vadodara
SHRI P. M. SARAIYA ( Alternate ) S H R I P. C. GOPINATH Travancore-Cochin Chemicals Ltd, Udyogamandal
S H R I C. N. G. N A I R ( Alternate ) S H R I A. R. JATANIA
D R A N I L PANDIT
All India Cast Iron Powder Mfgrs Association, Ahmadabad
Deepak Nitrite Ltd, Vadodara S H R I C. S. NAGAR ( Alternate )
DR P. G. PRADHAN S H R I T. S. KALAHASTY
Golden Chemicals Pvt Ltd, Bombay ( Alternate )
( Continued on page 17 )
2
IS : 247 - 1987
Indian Standard SPECIFICATION FOR
SODIUM SULPHITE, ANHYDROUS
(Fourth Revision)
0. F O R E W O R D 0.1 This Indian Standard ( Fourth Revision ) was adopted by the Bureau of Indian Standards on 28 May 1987, after the draft finalized by the Inorganic Chemicals ( Misc ) Sectional Committee had been approved by the Chemical Division Council.
0.2 Sodium sulphite, anhydrous, is used in water treatment, as a photographic developer, in paper industry, textile bleaching ( antichlor ) and as a dietary supplement.
0.3 The standard was first issued as a tentative standard in 1950 and subsequently revised in 1957, 1964 and 1972.
0.4 This standard has been revised again deleting the photographic grade, as a separate Indian Standard is being formulated by Photographic Materials Sectional Committee of BIS. A new spectrophotometry method has been prescribed as an alternate method for determination of iron.
0.5 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 accord-ance with IS : 2-1960*. The number of significant places retained in the rounded off value should be the same as that of the specified value in this standard.
1. SCOPE
1.1 This standard prescribes the requirements and the methods of sampling and test for sodium sulphite, anhydrous.
*Rules for rounding off numerical values ( revised ).
3
IS : 247 - 1987
2. GRADES
2.1 There shall be the following three grades of the material: a) Technical, b) Pure, and c) Analytical reagent.
3. REQUIREMENTS
3.1 Description — The material of all grades shall be in the form of a white granular powder free from extraneous matter. 3.2 Solution in Water — A freshly prepared aqueous solution of the material containing 20 g of the powder in 100 ml of carbon dioxide-free water shall be colourless and free from sediment other than a slight flocculence.
3.3 The material shall also comply with the requirements given in Table 1, when tested according to the methods prescribed in Appendix A. Reference to the relevant clauses of Appendix A is given in col 6 of the table.
TABLE 1 REQUIREMENTS FOR SODIUM SULPHITE, ANHYDROUS S L No.
(1) i)
ii)
iii)
iv)
v)
vi)
vii)
viii)
ix)
CHARACTERISTIC REQUIREMENT FOR G R A D E
Technical Pure Analytical
(2) Sodium sulphite ( Na2SO3 )
content, percent by mass, Min
Insoluble matter and metals other than alkali metals, percent by mass, Max
Free alkali ( as Na2O ), percent by mass, Max
Sodium thiosulphate ( as Na2S2O3 ), percent by mass, Max
Heavy metals ( as Pb ), percent by mass, Max
Iron ( as Fe ), percent by mass, Max
Arsenic ( as As2O3 ), percent by mass, Max
Chlorides ( as Cl ), percent by mass, Max
Free acid
(3) 92.0
–
2.0
–
0.02
0.02
—
—
—
(4)
95.0
– –
To pass test
0.002
—
0.001
—
—
Reagent (5)
98.0
0.02
0.1
0.05
0.001
0.001
0.000 5
0.02
To pass test
M E T H O D O F T E S T ( R E F
No. TO C L A U S E I N A P P E N -
DIX A )
(6) A-2
A-3
A-4
A-5
A-6
A-7
A-8
A-9
A-10
4
IS : 247 - 1987
4. PACKING AND MARKING
4.1 The material of technical and pure grade shall be packed in suitable air-tight containers, the maierial of analytical reagent grade shall preferably be packed in hard glass bottles closed with air-tight stoppers.
4.2 Each container shall be securely closed after filling and marked with the name of the manufacturer; grade and mass of the material in the container; recognized trade-mark, if any; and batch number or month and year of manufacture.
4.2.1 The analytical data of the material for the corresponding characteristics prescribed in Table 1 shall also be shown on the containers of the analytical reagent grade of the material.
4.2.2 The product may also be marked with Standard Mark.
4.2.3 The use of the Standard Mark is governed by the provisions of the Bureau of Indian Standards Act, 1986 and the Rules and Regulations made thereunder. The details of conditions under which the licence for the use of Standard Mark may be granted to manufactures or producers may be obtained from the Bureau of Indian Standards.
5. SAMPLING
5.1 The method of preparation of test sample and the criteria of conformity shall be as prescribed in Appendix B.
A P P E N D I X A ( Clause 3.3 )
METHODS OF TEST FOR SODIUM SULPHITE, ANHYDROUS
A-1. QUALITY OF REAGENTS
A-1.1 Unless specified otherwise, pure chemicals and distilled water ( see IS : 1070-1977* ) shall be employed in test.
N O T E — 'Pure chemicals' shall mean chemicals that do not contain impurities which affect the results of the analysis.
*Specification for water for general laboratory use ( second revision ).
5
IS : 247 - 1987
A-2. DETERMINATION OF SODIUM SULPHITE
A-2.0 Outline of the Method — A known excess of standard iodine solution is added to the material. The excess iodine solution is back titrated with thiosulphate solution. The iodine consumed in oxidizing the sulphite to sulphate gives a measure of the sulphite. A-2.1 Reagents
A-2.1.1 Standard Iodine Solution — 0.1 N ( see IS : 2316-1968* ).
A-2.1.2 Starch Indicator — Triturate 5 g of starch and 0.01 g of mercuric iodide with 30 ml of water in a mortar. Pour the resulting paste into one litre of boiling water, boil for three minutes, allow the solution to cool and decant off the clear liquid.
A-2.1.3 Standard Sodium Thiosulphate Solution — 0.1 N, freshly standardized ( see IS : 2316-1968* ). A-2.2 Procedure — Weigh accurately about 0.25 g of the material in a tared weighing bottle and add it to exactly 50 ml of standard iodine solution acidified with 2 ml of dilute hydrochloric acid. Allow to stand for 5 minutes and titrate the excess of iodine with standard sodium thiosulphate solution using starch solution as indicator, the end point of the reaction being indicated by the disappearance of blue colour. Carry out a blank titration without using the material. A-2.3 Calculation
Sodium sulphite ( Na2SO3 ) content, percent by mass =
where V1 = volume in ml of standard sodium thiosulphate solution
used in the blank titration, V2 = volume in ml of standard sodium thiosulphate solution
used with the material, N = normality of standard sodium thiosulphate solution, and M = mass in g of the material taken for the test.
A-3. DETERMINATION OF INSOLUBLE MATTER AND METALS OTHER THAN ALKALI METALS
A-3.0 Outline of the Method — Insoluble matter and metals, other than alkali metals, are determined by mixing the material with water, adding to the solution, ammonium oxalate, ammonium phosphate and ammonium hydroxide, and weighing the residue obtained on the filter.
*Methods of preparation of standard solutions for colorimetric and volumetric analysis ( first revision ).
6
IS : 247 - 1987
A-3.1 Reagents
A-3.1.1 Ammonium Oxalate Solution — 4 percent.
A-3.1.2 Ammonium Phosphate Solution — 10 percent.
A-3.1.3 Dilute Ammonium Hydroxide Solution — 1 : 9 ( v/v ).
A-3.1.4 Dilute Ammonium Hydroxide Solution — 1 : 39 ( v/v ).
A-3.2 Procedure — Dissolve about 10 g of the material, accurately weighed, in 75 ml of water. Add 5 ml of ammonium oxalate solution, 2 ml of ammonium phosphate solution, and 10 ml of dilute ammonium hydroxide ( 1 : 9 ) . Allow to stand overnight. Filter off the precipitate formed through an ashless filter paper and wash with dilute ammonium hydroxide ( 1 : 39 ). Dry the residue, ignite at about 600°C, cool in a desiccator and weigh.
A-3.3 Calculation
Insoluble matter and metals other than alkali metals, percent by mass =
where M1 = mass in g of the ignited residue, and M2 = mass in g of the material taken for the test.
A-4. DETERMINATION OF FREE ALKALI A-4.0 Outl ine of the Method — Sodium sulphite is oxidized to sodium sulphate using hydrogen peroxide and the free alkali is then titrated against standard acid.
A-4.1 Reagents
A-4.1.1 Hydrogen Peroxide — Approximately 30 percent ( m/v ), neutral to methyl red indicator.
A-4.1.2 Methyl Red Indicator — Dissolve 0.03 g of water soluble methyl red in water and dilute to 100 ml.
A-4.1.3 Standard Hydrochloric Acid — 0.1 N.
A-4.2 Procedure — Dissolve 5 g of the material, accurately weighed, in 50 ml of water and add 10 ml of hydrogen peroxide. Mix well, add a drop of methyl red indicator and titrate with standard hydrochloric acid. Run a blank without using the material.
7
IS : 247 - 1987
A-4.3 Calculation Free alkali ( as Na2O ),
percent by mass =
where
V1 = volume in ml of standard hydrochloric acid used in the test with the material,
V2 = volume in ml of standard hydrochloric acid used in the blank,
N = normality of standard hydrochloric acid, and M = mass in g of the material taken for the test.
A-5. TEST FOR SODIUM THIOSULPHATE
A-5.1 For Pure Grade
A-5.1.0 Outline of the Method — Thiosulphate gives with hydrochloric acid a turbidity due to white precipitate of sulphur which is taken as a test for thiosulphate.
A-5.1.1 Reagent
A-5.1.1.1 Concentrated hydrochloric acid — See IS : 265-1976*. A-5.1.2 Procedure — Dissolve 1 g of the material in 15 ml of water.
Add to it 5 ml of concentrated hydrochloric acid. Allow to stand for 5 minutes.
A-5.1.3 The material shall be taken to have passed the test if no turbidity is produced.
A-5.2 For Analytical Reagent Grade A-5.2.0 Outline of the Method — The opalescence produced by the
material with potassium bromide-mercurjc chloride reagent is compared with that produced by the standard sodium thiosulphate solution.
A-5.2.1 Apparatus
A-5.2.1.1 Nessler cylinders — 50 ml capacity.
A-5.2.2 Reagents A-5.2.2.1 Potassium bromide-mercuric chloride reagent — Dissolve 25 g
each of potassium bromide and mercuric chloride in 900 ml of water at about 50°C. Cool, dilute to one litre and allow to stand overnight. Filter, if necessary, to obtain a perfectly clear solution.
*Specification for hydrochloric acid ( second revision ).
8
IS : 247 - 1987
A-5.2.2.2 Standard sodium thiosulphate solution — Dilute 50 ml of exactly 0.1 N sodium thiosulphate ( Na2S2O3.5H2O ) solution ( see A-2.1.3 ) to one litre.
A-5.2.3 Procedure — Dissolve 10.0 g of the material in water and dilute to exactly 100 ml. Slowly pipette out 0.5 ml of the solution into a Nessler cylinder containing 10 ml of potassium bromide-mercuric chloride reagent. In a second Nessler cylinder containing 10 ml of potassium bromide-mercuric chloride reagent, add 0.2 ml of standard sodium thiosulphate solution. Let both cylinders stand for 10 minutes without agitation. Then carefully agitate to distribute the opalescence and examine immediately ( see Note ).
N O T E — If the solutions stand for more than 15 minutes, secondary reactions may take place, vitiating results.
A-5.2.3.1 The limit prescribed in Table 1 shall be taken as not having been exceeded if the opalescence produced with the material is not greater than that in the control test.
A-6. TEST FOR HEAVY METALS
A-6.0 Outline of the Method — The colour produced by heavy metals with hydrogen sulphide is compared with that produced with standard lead solution under identical conditions.
A-6.1 Apparatus
A-6.1.1 Nessler Cylinders — 50 ml capacity.
A-6.2 Reagents A-6.2.1 Concentrated Hydrochloric Acid — See IS : 265-1976*.
A-6.2.2 Dilute Ammonium Hydroxide — approximately 10 percent ( m/m ).
A-6.2.3 Hydrogen Peroxide — approximately 6 percent ( m/v ).
A-6.2.4 Potassium Cyanide Solution — Dissolve 10 g of potassium cyanide in 90 ml of water, add 2 ml of hydrogen peroxide, allow to stand for 24 hours and make up the volume to 100 ml with water.
A-6.2.5 Acetic Acid — approximately 33 percent by mass. A-6.2.6 Concentrated Nitric Acid — See IS : 264-1976†.
*Specification for hydrochloric acid ( second revision ). †Specification for nitric acid ( second revision ).
9
IS : 247 - 1987
A-6.2.7 Standard Lead Solution — Dissolve 1.60 g of lead nitrate in water, add 1 ml of concentrated nitric acid and make up the volume to 1 000 ml. Pipette out 10 ml of this solution and dilute again to 1 000 ml with water. One millilitre of this solution contains 0.01 mg of lead ( as Pb ).
A-6.2.8 Sodium Sulphide Solution — approximately 10 percent ( m/v ), freshly prepared. A-6.3 Procedure — Dissolve 0.5 g of the material of technical grade and 5.0 g of the material of other grades, in 30 ml of hot water, add 20 ml of concentrated hydrochloric acid and evaporate the contents nearly to dryness on a water-bath add 15 ml of hot water and 3 ml of concentrated hydrochloric acid, again evaporate on a water-bath and then heat for one hour at 150±2°C. Extract the residue with water, filter and make up the filtrate to 25 ml. Take 5 ml of the filtrate in a Nessler cylinder. Make it alkaline to litmus by gradual addition of dilute ammonium hydroxide and then add 1 ml of potassium cyanide solution. Carry out a control test in the other Nessler cylinder using 2 ml of standard lead solution ( 1 ml for analytical reagent grade ) in place of the material and the same quantities of other reagents. Add 1 ml of acetic acid to both the solutions and make up the volume to 50 ml with water. Add 2 drops of sodium sulphide solution. Mix thoroughly and compare the colours produced in the two cylinders.
A-6.3.1 The limit prescribed 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 control test.
A-7. TEST FOR IRON A-7.0 Two methods are prescribed, namely:
a) Colorimetric Method, and b) Spectrophotometric Method.
A-7.1 Colorimetric Method A-7.1.0 Outline of the Method — Ferric iron gives a red colour with
potassium thiocyanate. The colour produced by the material after oxidation is compared with the colour formed by a standard iron solution.
A-7.1.1 Apparatus
A-7.1.1.1 Nessler cylinders — 50 ml capacity. A-7.1.2 Reagents
A-7.1.2.1 Concentrated hydrochloric acid — See IS : 265-1976*.
*Specification for hydrochloric acid ( second revision ).
10
IS : 247 - 1987
A-7.1.2.2 Ammonium persulphate or potassium persulphate
A-7.1.2.3 Butanolic potassium thiocyanate solution — Dissolve 10 g of potassium thiocyanate in 10 ml of water. Add sufficient n-butanol to make up the volume to 100 ml and shake vigorously until the solution is clear.
A-7.1.2.4 Standard iron solution — Dissolve 0.702 g of ferrous ammonium sulphate [ Fe ( NH 4 )2, ( SO4 )2 . 6H2O ] in 10 ml of dilute sulphuric acid ( 10 percent v/v ) and dilute with water to 1 000 ml. Pipette out 10 ml of the solution and dilute with water to make up the volume to 100 ml. One millilitre of this solution contains 0.01 mg of iron ( as Fe ).
A-7.1.3 Procedure — Pipette out 5 ml of the solution prepared in A-6.3 in a Nessler cylinder. Add 1 ml of concentrated hydrochloric acid, about 30 mg of ammonium persulphate or potassium persulphate and 15 ml of butanolic potassium thiocyanate solution. Shake vigorously for 30 seconds and allow the liquids to separate. Carry out a control test in another Nessler cylinder using the following volumes of standard iron solution in place of the material:
a) Two ml for technical grade, and b) One ml for analytical reagent grade. A-7.1.3.1 The limit prescribed in Table 1 shall be taken as not
having been exceeded if the intensity of any red colour produced in the butanolic layer in the test with the material is not greater than that produced in the control test. A-7.2 Spectrophotometric Method
A-7.2.0 Outline of the Method — Iron is reduced to ferrous state by thioglycollic acid and then treated with excess of ammonium hydroxide. The intensity of the resultant pink coloured complex is measured in a spectrophotometer at 535 nm at pH 10.
A-7.2.1 Apparatus A-7.2.1.1 Any suitable spectrophotometer.
A-7.2.2 Reagents A-7.2.2.1 Dilute sulphuric acid — 10 percent ( v/v ).
A-7.2.2.2 Standard iron solution —- Weigh 0.702 g of ferrous ammonium sulphate [ FeSO4 ( NH 4 )2 SO4.6H2O ] and dissolve in 10 ml of dilute sulphuric acid. Dilute with water to make up the volume to 1 000 ml. Transfer 10 ml of this solution and again dilute with water to make up the volume to 100 ml. One ml of this solution is equivalent to 0.01 mg of iron ( as Fe ).
11
IS : 247 - 1987
A-7.2.2.3 Concentrated hydrochloric acid — See IS : 265-1976*. A-7.2.2.4 Dilute ammonium hydroxide — approximately 6 N. A-7.2.2.5 Thioglycollie acid AR — 10 percent (v/v).
( SHCH 2 COOH )
A-7.3 Procedure — Weigh about 10 g of the sample, dissolve in about 75 ml of water. Add 5 ml of concentrated hydrochloric acid and boil for two minutes. Cool to 15°C and add 10 ml of 10 percent thioglycollic acid solution. Add dilute ammonium hydroxide solution drop by drop till pale pink colour appears keeping the temperature of the solution below 15°C. Add one millilitre more of dilute ammonium hydroxide solution to bring the pH to about 10. Dilute to 100 ml in a standard volumetric flask. Read the intensity of the colour in a spectrophotometer using 535 nm wavelength. Note down the reading. Run a blank on all the reagents following the above procedure. Subtract this reading from the reading obtained with the sample. Let this be A.
A-7.3.1 Prepare a series of standard iron solution by taking 2, 5, 7, 10, 15 and 20 of standard iron solution. Subject them to above procedure and note down the readings. Plot a standard curve for readings obtained against concentration of iron ( as Fe ).
A-7.4 Calculation
Iron ( as Fe ), percent by mass =
where A = mg of Fe from the calibration curve, and
M = mass in g of prepared sample taken for test.
A-8. TEST FOR ARSENIC A-8.0 Outl ine of the Method — The stain produced by arsenic on a mercuric bromide paper is compared with stains produced by standard arsenic solution. A-8.1 Reagent
A-8.1.1 Concentrated Sulphuric Acid — See IS : 266-1977†. A-8.2 Procedure
A-8.2.1 Preparation of solution — Dissolve in 50 ml of water 1.00 g of the material of pure grade and 2.00 g of the material of analytical reagent grade. Add 5 ml of concentrated sulphuric acid and evaporate to about 15 ml.
*Specification for hydrochloric acid ( second revision ). †Specification for sulphuric acid ( second revision ).
12
IS : 247 - 1987
A-8.2.2 Carry out the test for arsenic as prescribed in IS : 2088-1983* using 0 01 mg of arsenic trioxide (As2O3 ) for preparing the standard stain.
A-8.2.3 The limit prescribed in Table 1 shall be taken as not having been exceeded if the length of the stain as well as intensity of its colour produced in the test with material are not greater than those produced in the control test.
A 9. TEST FOR CHLORIDES
A-9.0 Outline of the Method — The opalescence or turbidity produced by the material with silver nitrate is compared with that produced by standard sodium chloride solution under identical conditions of test.
A-9.1 Apparatus A-9.1.1 Nessler Cylinder — 50 ml capacity.
A-9.2 Reagents A-9.2.1 Hydrogen Peroxide — 30 percent ( m/v ). A-9.2.2 Concentrated Nitric Acid — See IS : 264-1976†.
A-9.2.3 Silver Nitrate Solution — 2 percent.
A-9.2.4 Standard Chloride Solution — Dissolve 0.164 7 g of sodium chloride, previously dried at 105 ± 5°C, in water and make up the volume to 1 000 ml. Pipette out 10 ml of this solution and dilute again to 100 ml. One millilitre of this solution is equivalent to 0.01 mg of chloride ( as Cl ). A-9.3 Procedure — Dissolve 1.00 g of the material in 10 ml of water. Make up the volume to 100 ml. Transfer 10 ml of the solution to a Nessler cylinder, add 2 ml of hydrogen peroxide and allow to stand for 30 minutes. Add 2 ml of concentrated nitric acid and 1 ml of silver nitrate solution. Carry out a control test using 2 ml of standard chloride solution in place of the material. Compare the opalescence or turbidity produced in the two tubes five minutes after the addition of silver nitrate solution.
A-9.3.1 The limit prescribed in Table 1 shall be taken as not having been exceeded if the opalescence or turbidity produced in the test with the material is not greater than that produced in the control test.
A-10. TEST FOR FREE ACID A-10.0 Outline of the Method — The development of pink colour on adding phenolphthalein to a solution of the material is taken to indicate absence of free acidity.
*Methods for determination of arsenic ( second revision ). †Specification for nitric acid ( second revision ).
13
IS : 247 - 1987
A-10.1 Reagent
A-10.1.1 Phenolphthalein Indicator — Dissolve 0.1 g of phenolphthalein in 60 ml of rectified spirit ( see IS : 323-1959* ) and dilute with water to 100 ml.
A-10.2 Procedure — Dissolve 1.00 g of the material in 15 ml of water and add two drops of phenolphthalein indicator.
A-10.2.1 The material shall be taken to have passed the test if a pink colour is produced on the addition of phenolphthalein.
A P P E N D I X B ( Clause 5.1 )
SAMPLING AND CRITERIA FOR CONFORMITY
B-1. GENERAL REQUIREMENTS FOR SAMPLING
B-1.0 In drawing, preparing, storing and handling test samples, the following precautions shall be observed. B-1.1 Samples shall not be taken at a place exposed to weather. B-1.2 Precautions shall be taken to protect the samples, the material being sampled, the sampling instrument and the containers for samples from adventitious contamination. B-1.3 To draw a representative sample, the contents of each container selected for sampling shall be mixed thoroughly by suitable means. B-1.4 The samples shall be placed in suitable, clean, dry and air-tight opaque glass or plastic containers. B-1.5 The sample containers shall be of such a size that they are almost completely filled by the sample.
B-1.6 Each sample container shall be sealed air-tight after filling and marked with full details of sampling, the date of sampling and the year of manufacture. B-1.7 Samples shall be stored in such a manner that the temperature of the material does not vary unduly from the normal temperature.
B-2. SCALE OF SAMPLING B-2.1 Lot — All the containers in a single consignment of the material drawn from a single batch of manufacture shall constitute a lot. If a
*Specification for rectified spirit ( revised ). 14
IS : 247 - 1987
consignment is declared to consist of different batches, the batches shall be marked separately and the group of containers in each batch shall constitute separate lots.
B-2.2 From each lot, five containers shall be selected ( B-2.2.1 ) for drawing samples for test. In case the lot contains less than five containers, each container shall be tested.
B-2.2.1 Arrange the containers in a lot in a systematic way and starting from any container, count them as 1, 2, 3 and so on. Every rth container thus counted shall be separated for drawing for test, where
NOTE — In case the value of r comes out to be a fractional number, it shall be taken as equal to the integral part of that value.
B-3. PREPARATION OF TEST SAMPLES
B-3.1 Drawing of Samples — Draw a representative sample from each container selected.
B-3.1.1 Mix portions of the material drawn from the same container to prepare the test sample representing the container. The quantity of material to be darwn from each container shall be sufficient to conduct all the tests given in 3.3 and shall be not less than 200 g.
B-3.1.2 The samples shall be stored in dry glass bottles or other suitable containers, sealed air-tight and labelled with all the particulars of sampling given in B-1.6.
B-3.1.3 Five test samples, representing the five containers selected as in B-2.2, shall constitute a set of test samples.
B 4. NUMBER OF TESTS
B-4.1 For Technical Grade — Tests for the determination of sodium sulphite shall be conducted on each of the five test samples ( see B-3.1.3 ). Tests for all other characteristics prescribed in 3 and Table 1 shall be conducted on a composite test sample, prepared by mixing equal quantities of material from each of the five test samples.
B-4.2 For Pure Grade — Tests for the determination of sodium sulphite, heavy metals and arsenic shall be conducted on each of the five test samples ( see B-3.1.3 ). Tests for all other characteristics prescribed in 3 and Table 1 shall be conducted on the composite sample ( see B-4.1 ). B-4.3 For Analytical Reagent Grade — Tests for the determination of sodium sulphite and free alkali shall be conducted on each of the five test samples ( see B-3.1.3 ). Tests for all other characteristics prescribed in 3 and Table 1 shall be conducted on the composite sample ( B-4.1 ).
15
IS : 247 - 1987
B-5. CRITERIA FOR CONFORMITY
B-5.1 Teats Carried Out on Five Test Samples
B-5.1.1 Sodium Sulphite — From the test results for sodium sulphite, the mean ( ) and range ( R ) of test results shall be calculated ( range being denned as the difference between the maximum and the minimum values of test results ). The lot shall be considered to have passed if the value of the expression ( — 0'6 R ) is equal to or greater than the respective limit prescribed in Table 1.
B-5.1.2 Free Alkali — From the test results for free alkali, the mean ( ) and range ( R ) of test results shall be calculated. The lot shall be considered to have passed if the value of the expression ( -f-0'6 R ) is equal to or less than 0 1 .
B-5.1.3 Heavy Metals, Iron and Arsenic — The lot shall be considered to have passed for the characteristics tested ( see B-4.2 and B-4.3 ) if each test sample passes the corresponding test prescribed.
B-5.2 Test Carried Out on Compos i te Test Sample — The lot shall be considered to have passed in respect of the characteristics tested on the composite test sample ( see B-4.1 to B-4.4 ) if the composite test sample satisfies the corresponding tests prescribed.
B-5.3 The lot shall be considered as conforming to the specification if it satisfies all the criteria given in B-5.1 and B-5.2.
16
IS : 247 - 1987
( Continued from page 2 )
Members Representing S H R I R. R. R A Y Waldies Ltd, Calcutta
SHRI S. K. BARAT ( Alternate ) DR H. C. SHAH 3 K Chemical Co, Thane
SHRIMATI K. H. SHAH ( Alternate ) SHRI S. R. SINGH Development Commissioner, Small Scale Industries,
New Delhi SHRI J . C. PASRIJA ( Alternate )
SHRI S. S. SINGHANIA Forum of Small Scale Entreprenuers, Calcutta SHRI B. L. KANODIA ( Alternate )
DR J. K. SINHA Central Mining Research Station ( CSIR ), Dbanbad SHRI V. B. SONI Electrolytic Manganese Co ( Division of Union
Carbide India Ltd ), Thane S H R I D. G H O S H ( Alternate )
DR M. S. VAIDYA Dharamsi Morarji Chemical Co Ltd, Bombay S H R I R. S. V Y A S ( Alternate )
17
M G I P F — 2 0 9 Deptt. of BIS/2007 – 9 - 7 - 2 0 0 7 – 1 0 0 Books
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