3199 NTERNATIONAL STANDARD Tso INTERNATIONAL ORGANIZATION FOR STANDARDIZATION MEKIYHAPOJIHAH OPTAHM3ALIMA TIO CTAHIAPTW3ALIMM.ORGANISATION INTERNATIONALE DE NORMALISATION Sodium chlorate for industrial use -- Determination of chlorate content --- Dichromate titrimetric method Chlorate de sodium a usage industriel -- Dosage du chlorate -- Meéthode titrimétrique au dichromate First edition - 1975-02-15 ANsr Internat Doc Sect MAR 2 4 1975 ISO 3199-1975 (E) UDC ·661.442 : 546.135 : 543.24 Ref. No. ISO 3199-1975 (E) Descriptors : sodium chlorate, chemical analysis, determination of content, chlorates, volumetric analysis. Price based on 2 pages from IHS Not for Resale FOREWORD IsO (the International Organization for Standardization) is a woridwide federation of national standards institutes (IsO 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. International organizations, governmental and non-governmental, in liaison with IsO, aiso take part in the work. Draft International Standards adopted by the Technical Committees are circulated to the Member Bodies for approval before their acceptance as International Standards by the ISO Council. International Standard isO 3199 was drawn up by Technical Committee ISO/TC 47, Chemistry, and circulated to the Member Bodies in September 1973. It has been approved by the Member Bodies of the following countries : Austria India South Africa, Rep. of Betgium Ireland Spain Bulgaria Italy Switzerland Chile Netherlands Thailand Czechoslovakia New Zealand Turkey France Poland United Kingdom Germany Portugal U.S.S.R. Hungary Romania Yugoslavia No Member Body expressed disapproval of the document. @ International Organization for Standardization, 1975 Printed in Switzerland Copyright International Organization for Standardization from IHS ISO 3199-1975 (E) INTERNATIONAL STANDARD Sodium chlorate for industrial use --- Determination of chlorate content -- Dichromate titrimetric method 1 SCOPE AND FIELDOF APPLICATION and cooled in a desiccator. Dissolve in water, dilute to the mark in a 1 000 ml one-mark volumetric flask and mix. This International Standard specifies a dichromate Store this solution in a glass bottle fitted with a ground titrimetric method for the determination of the chlorate content of sodium chlorate for industrial use. glass stopper. The method is not applicable to the analysis of mixtures for 3.6 Barium diphenylamine-4-suiphonate, 4 g/l solution. agricultural use such as herbicides, pesticides, etc., in which certain constituents may cause interference. 4 APPARATUS 2 PRINCIPLE Ordinary laboratory apparatus. Reduction of the chlorate by a known quantity, in excess, of an iron(ll) salt. 5 PROCEDURE Titration of the excess of iron(ll) salt with a standard volumetric solution of potassium dichromate in the 5.1 WARNING presence of barium diphenylamine-4-sulphonate solution as Sodium chlorate induces combustion. Avoid storing or indicator. handling it near a source of heat. Aiso avoid all contact of the product or its solutions with acids or combustible 3 REAGENTS materiats (paper, cardboard, ciothing, wood, rags, fatty matter, etc.) which may ignite or subsequantiy form an During the analysis, use only reagents of recognized explosive mixture. materials are accidentally any analytical reagent grade and only distilled water or water of impregnated with sodium chlorate, flush them with water. equivalent purity. 5.2 Test portion 3.1 Orthophosphoric acid, p approximately 1,71 g/ml, about 85 % (m/m) solution. Weigh, to the nearest 0,001 g, approximately 3 g of the test sample. 3.2 Sulphuric acid, p approximately 1,84 g/ml, about 96 % (m/m) solution or approximately 36 N. 5.3 Blank test Carry out at the same time as the determination, following 3.3 Sulphuric acid, approximately 18 N solution.