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IS0
INTERN AT I ON A L O R G A N 1 Z AT I O N FOR S TA N DARD 1 ZAT I O N
IS0 RECOMMENDATION
R 908
HYDROCHLORIC ACID FOR INDUSTRIAL USE
DETERMINATION OF OXIDIZING OR REDUCING SUBSTANCES
Volumetric method
1st EDITION
December 1968
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The copyright of IS0 Recommendations and IS0 Standards
belongs to IS0 Member Bodies. Reproduction of these
documents, in any country, may be authorized therefore only
by the national standards organization of that country, being
a member of ISO.
For each individual country the only valid standard is the national standard of that country.
Printed in Switzerland
in French and Russian. Copies to be obtained through the national standards organizations.
Also issued
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BRIEF HISTORY
The IS0 Recommendation R 908, Hydrochloric acid for industrial use - Determination of
oxidizing or reducing substances - Volumetric method, was 'drawn up by Technical Committee
ISO/TC 47, Chemistry, the Secretariat of which is held by the Ente Nazionaie Italian0 di Unificazione
(UNI).
Based on detailed work on this question carried out by the Technical Committee, a Draft IS0
Recommendation was adopted in 1965.
In June 1967, this Draft IS0 Recommendation (No. 11 78) was circulated to all the IS0 Member
Bodies for enquiry. It was approved, subject to a few modifications of an editorial nature, by the
following Member Bodies :
South Africa, Rep. of
Austria Iran
Belgium Ireland Spain
Switzerland
Bulgaria Israel
Thailand
Chile Italy
Turkey
Cuba Japan
U.A.R.
Czechosiovakia Korea, Dem. P. Rep. of
France Netherlands United Kingdom
New Zealand U.S.S.R.
Germany
Poland Yugoslavia
Hungary
Portugal
ICAITI*
Romania
India
No Member Body opposed the approval of the Draft.
The Draft IS0 Recommendation was then submitted by correspondence to the IS0 Council
which decided, in December 1968, to accept it as an IS0 RECOMMENDATION.
*
Institut0 Centroamericano de Investigacidn y Tecnologia Industrial (Costa Rica, Guatemala, Honduras, Nicaragua,
El Salvador, Panama).
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ISO/R 908-1968 (E)
IS0 Recommendation R 908 Decem ber 1968
HYDROCHLORIC ACID FOR INDUSTRIAL USE
D ETE RM I NAT
ON OF OXIDIZING OR REDUCING SUBSTANCES
Volumetric method
1. SCOPE
This IS0 Recommendation describes a volumetric method for the determination of oxidizing or
reducing substances in hydrochloric acid for industrial use.
2. PRINCIPLE
Preliminary qualitative, test to detect the presence of either oxidizing or reducing substances.
Iodometric determination directly (in the case of oxidizing substances) or indirectly (in the case of
reducing substances).
3. REAGENTS
Distilled water or water of equivalent purity recently boiled and cooled should be used in the
test.
3.1 Potassium iodide, crystals.
3.2 Potassium iodide, 100 g/l solution.
Dissolve 1 O g of potassium iodide in water and dilute to 1 O0 ml.
3.3 Sodium thiosulphate, O. 1 N standard volumetric solution.
(see Note, section 6).
3.4 Iodine, 0.1 N standard volumetric solution, containing at least 25 g/l of potassium iodide.
(see Note, section 6).
3.5 Starch solution
Make a paste of 0.5 g of starch with 2.5 ml of water.
Pour the paste in small quantities at a time into 200 ml of water.
Boil for 15 minutes with constant stirring. Preserve in small containers previously sterilized in
boiling water for 2 hours.
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