910 ISO NTERNATIONAL STANDARD INTERNATIONAL ORGANIZATION FOR STANDARDIZATION MEKIYHAPOIHA OPIAH3ALIH HIO CTAHIAPTW3ALIH.ORGANISATION INTERNATIONALE DE NORMALISATION Sulphuric acid and oleum for industrial use -- Determination of total acidity, and calculation of free sulphur trioxide content of oleum - Titrimetric method Acide sulfurique et oléums a usage industriel -- Détermination de I'acidite totale et calcul de la teneur en trioxyde desoufrelibredesoleums-Methodetitrimetrique First edition - 1977-11-15 NOV 1 7 1977 KNsi Internat Doc Sect Ref. No. ISO 910-1977 (E) UDC 661.25 : 543.241 Descriptors : sulphuric acid, chemical analysis, determination of content, acidity, volumetric analysis. Price based on 3 pages Copyright International Organization for Standardization Notfor Resale FOREWORD Iso (the International Organization for Standardization) is a worldwide federation of national standards institutes (sO member bodies). The work of developing International Standards is carried out through ISO technical committees. Every member body interested in a subject for which a technical committee has been set up has the right to be represented on that committee. Internationa! organizations, governmental and non-governmental, in liaison with IsO, also take part in the work. Draft International Standards adopted by the technicai committees are circulated to the member bodies for approvai before their acceptance as International Standards by the Iso Council. Prior to 1972, the results of the work of the technical committees were published as IsO Recommendations; these documents are in the process of being transformed into International Standards. As part of this process, Technical Committee it technically suitabie for transformation. International Standard ISO 910 therefore repiaces iS0 Recommendation R 910-1968 to which it is technically identical. ISO Recommendation R 910 had been approved by the member bodies of the following countries : Hungary Austria Portugal Belgium India Romania Brazil Iran South Africa, Rep. of Chile Ireland Spain Cuba Italy Switzerland Czechoslovakia Japan Thailand Egypt, Arab Rep. of Netherlands Turkey France New Zealand U.S.S.R. Germany Poland Yugoslavia The member body of the following country had expressed disapproval of the Recommendation on technical grounds : United Kingdom The member body of the United Kingdom also disapproved the transformation of the Recommendation into an International Standard. @ International Organization for Standardization,1977 Printed in Switzeriand Copyright International Organization for Standardization Not for Resale ISO 910-1977 (E) INTERNATIONAL STANDARD Sulphuric acid and oleum for industrial use -- Determination of total acidity, and calculation of free sulphur trioxide content of oleum -- Titrimetric method 1 SCOPE 5.3 Burette, graduated in 0,05 ml, complying with ISO 385. This International Standard specifies a titrimetric method for the determination of the total acidity of sulphuric acid 5.4 Conical flask, capacity 500 ml, with ground glass for industrial use, conventionally expressed as H2sO4, and stopper. a method for the calculation of the free sulphur trioxide content of oleum. 2 FIELD OF APPLICATION Two cases are considered : a) H2sO4 contents equal to or lower than 98 % (m/m); b) H,SO4 contents higher than 98 % (m/m). 3 PRINCIPLE ww Oxidation of a test portion with hydrogen peroxide and titration of the total acidity with a standard volumetric 09 sodium hydroxide solution, in the presence of methyl red as indicator. 4 REAGENTS During the analysis, use only reagents of recognized analytical grade, and only distilled water or water of equivalent purity, neutral to methy! red. 4.1 Hydrogen peroxide, 60 g/l solution, neutral to methyl red. 4.2 Sodium hydroxide, 1 N standard volumetric solution. 4.3 Methyl red, 1 g/l solution in 95 % (V/V) ethanot. FIGURE -Spherical glass ampoule 5 APPARATUS Ordinary laboratory apparatus and 6 PROCEDURE 5.1 Flask, capacity appr