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UDC 661.25 : 620.1
IS0
FOR STA N DARD IZATl ON
O RG A N IZATl O N
I N TERN AT1 O N A L
I SO R ECO M M EN DATI O N
R 911
SULPHURIC ACID FOR INDUSTRIAL USE
EVALUATION OF SULPHURIC ACID CONCENTRATION
BY MEASUREMENT OF DENSITY
1st EDITION
December 1968
COPYRIGHT RESERVED
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
Also issued in French and Russian. Copies to be obtained through the national standards organizations.
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BRIEF HISTORY
The IS0 Recommendation R 91 1, Sulphuric acid for industrial use - Evaluation of sulphuric
acid concentration by measurement of density, was drawn up by Technical Committee ISO/TC 47,
Chemistry, the Secretariat of which is held by the Ente Nazionale 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. 1181) 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 :
Austria India South Africa, Rep. of
Belgium Iran Spain
Brazil Ireland Switzerland
Chile Thailand
Italy
Cuba
Japan Turkey
Czechoslovakia Netherlands
U.A.R.
France
New Zealand U.S.S.R.
Germany Poland Yugoslavia
Hungary Portugal
ICAITI* Romania
One Member Body opposed the approval of the Draft :
United Kingdom
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 Investigacion y Tecnologia Industrial (Costa Rica, Guatemala, Honduras, Nicaragua,
El Salvador, Panama).
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ISO/R 91 1-1968 (1
I SO Recommendation R 911 Decem ber 1968
SULPHURIC ACID FOR INDUSTRIAL USE
EVALUATION OF SULPHURIC ACID CONCENTRATION
BY MEASUREMENT OF DENSITY
1. SCOPE
This IS0 Recommendation describes a method for the evaluation of H,SO, concentration of sul-
phuric acid for industrial use, by measurement of density.
2. PRINCIPLE
Determination of the density at 20 OC by means of a hydrometer. Evaluation of the corresponding
H, SO, concentration.
3. APPARATUS
Ordinary laboratory apparatus and
3.1 Hydrometer, calibrated at 20 OC, graduated in 0.005 g/ml.
4. PROCEDURE
4.1 Determination of density
Place approximately 500 ml of the test sample in a glass cylinder. Adjust the temperature of the
sample to 20 f 0.5 OC. Plunge in the hydrometer (3.1) and carry out the reading as soon as
static and thermal equilibrium have been reached.
4.2 Evaluation of H,SO, concentration
From the determined density (4.1) read from the attached Table the corresponding H,SO,
concentration as a percentage by mass.
5. EXPRESSION OF RESULTS
State the density read on the hydrometer, expressed in gramme
...