TSO 2762 NTERNATIONAL STANDARD INTERNATIONAL ORGANIZATION FOR STANDARDIZATION ·MEKAYHAPOIHA OPTAHH3ALIM IIO CTAHIAPTH3AIHM.ORGANISATION INTERNATIONALE DE NORMALISATION Hydrochloric acid for industrial use - Determination of soluble sulphates -- Turbidimetric method First edition - 1973-11-01 OCT 1 6 1973 ANs internat Loc Sect UDC 661.419 : 546.226 : 543.43 Ref. No. ISO 2762-1973 (E) Descriptors : hydrochloric acid, chemical analysis, determination of content, sulphates, turbidimetric method. Price based on 3 pages nsefromIHS Not for Resale FOREWORD ISO (the International Organization for Standardization) is a worldwide 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, also take part in the work. to the Member Bodies for approval before their acceptance as International Standards by the tsO Council. Standard ISO 2762 was drawn up by Technical Committee International ISO/TC 47, Chemistry, and circulated to the Member Bodies in April 1972. It has been approved by the Member Bodies of the following countries : Austria Ireland South Africa, Rep. of Belgium Israel Spain Czechostovakia Italy Sweden Egypt, Arab Rep. of Netherlands Switzerland France New Zealand Thailand Germany Poland Turkey Hungary Portugal United Kingdom India Romania U.S.S.R. This International Standard has also been approved by the International Union of Pure and Applied Chemistry (IUPAC). No Member Body expressed disapproval of the document. @ International Organization for Standardization, 1973 Printed in Switzerland Copyright International Organization for Standardization Not for Resale ISO 2762-1973 (E) INTERNATIONAL STANDARD Hydrochloric acid for industrial use - Determination of soluble sulphates -- Turbidimetric method 1SCOPE Transfer 20,80 mi of 0,1 N standard volumetric sulphuric acid solution to a 1 000 ml one-mark volumetric flask, dilute This Internationa! Standard specifies a turbidimetric to the mark and mix. method for the determination of soluble sulphates in 1 ml of this standard solution contains 0,1 mg of SO4 hydrochloric acid for industrial use. 5 APPARATUS 2 FIELD OF APPLICATION Ordinary laboratory apparatus and The method is applicable to products containing less than 0,1 % (m/m) of soluble sulphates, expressed as SO4.1) 5.1 Spectrophotometer, or 5.2 Photoelectric absorptiometer, fitted with filters, giving 3 PRINCIPLE only a negligible transmission below 450 nm and above Evaporation of a test portion to dryness and solution of the 550 nm. residue in hydrochloric acid. Measurement of the turbidity obtained by precipitation, 6 PROCEDURE under well-defined conditions,of barium sulphate. 6.1 Test portion 4 REAGENTS Weigh, to the nearest 0,01 g, a quantity of the test sample containing 0,5 to 4 mg of sO4. Distilled water, or water of equivalent purity, shall be used in the test. If the test sample is turbid, first pass it through a dry filter, collecting the filtrate in a dry receiver, discarding the first 4.1 Barium chloride dihydrate, of uniform particle size portions of the filtrate. between 0,50 and 1,25 mm, standardized by screening. NOTE -- In this case any sulphates contained in the insoluble matter It is essential that all preparations concerning are not determined. the determination and standardization shalt be carried out using 6.2 Blank test a product of the same particle size distribution. At the same time as the determination, carry out a blank 4.2 Sodium carbonate, approximately N solution. test, following the same procedure and using the same quantities of all the reagents used for the determination, 4.3 Hydrochloric acid, approximately N solution. but replacing the test portion by 5 ml of the sulph