Sh99h00 E06T58 E9-2 1d E5E9 INTERNATIONALSTANDARDISO6353/2-1983/ADDENDUM2 Publie 1986-11-15 TION INTERNATIONALEDENORMALISATION Reagents for chemical analysis Part 2: Specifications - First series Reactifs pour analyses chimiques -- Partie 2: Spécifications -- Premiere serie ADDENDUM 2 Foreword ISo (the International Organization for Standardization) is a worldwide federation of national standards bodies (iSO member bodies) The work of preparing international Standards is normally carried out through Iso technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. Inter- national organizations, governmental and non-governmental, in liaison with iso, also take part in the work. Draft International Standards adopted by the technical committees are circulated to the member bodies for approval before their ac- ceptance as International Standards by the Iso Council. They are approved in accordance with Iso procedures requiring at least 75 % approval by the member bodies voting. Addendum 2 to International Standard ISO 6353/2-1983 was prepared by Technical Committee ISO/TC 47, Chemistry. Users should note that all International Standards undergo revision from time to time and that any reference made herein to any other International Standard implies its latest edition, unless otherwise stated. s0 6353/2-1983/Add. 2-1986 (E) UDC 543.4 Ref.No. ISO6353/2-1983/Add.2-1986 (E) Descriptors : chemical analysis, chemical reagents, specifications, tests. @ International Organization for Standardization, 1986 right International Organization for Standardizatior Price based on 1 page se from IHS 6353 PT 2-83 E06TSah 5 990 8 ISO6353-1983/Add.2-1986(E) PS 30 Sodium carbonate, primary standard Na2CO3 Relative molecular mass: 105,988 PS30.1 Specification Weigh, to the nearest 0,000 1 g, about 0,93 g of the sodium carbonate, and dissolve it in 150 ml of water. Add, using a Assay (Na2CO3, after drying at 285 °C) ... 99,95 to 100,05 % 25 ml burette graduated in 0,05 ml divisions and complying with class A of IS0 385/1, 16,00 ml of the hydrochloric acid The mean value of the assay shall be in the range 99,95 solution, cautiously and while stirring, and then heat to boiling. to 100,05 % and the standard deviation shall not exceed Cool and titrate, using the same burette, with the same ±0,05 %. hydrochloric acid solution according to GM 31.2. Use the same potentiometer, accurate as in Ps 30.2.1. Operate at the calibra- All other properties shall comply with the requirements for tion temperature of the burette (for example 20 ± 1 oC). reagent R 30. Theassay,expressedasapercentagebymassofNazcO3,is given by the formula PS 30.2 Test 5,299 4 V2 c m2 Ps 30.2.1 Standardization of hydrochloric acid solution, c(HCl) = 1 mol/I where Weigh, to the nearest 0,000 1 g, about 1,9 g of electrolytic is the total volume,in millilitres,of hydrochloric acid silver(99,995%),anddissolve itin10mlofnitricacid(R19)by solution used for the determination; gently heating. Cool and dilute to about 80 ml with water. Titrate withhydrochloric acid solution,c(HCl) 1mol/1, cisthe concentration,inmolesof HCl perlitre,of according.toGM31.2.Useapotentiometeraccurateto hydrochloric acid solution used; ±1mVanda25mlburettegraduated in0,05mldivisionsand complying with class A of 1s0 385/1. Operate at the calibration m2 is the mass, in grams, of sodium carbonate weighed. temperature of the burette (for example 20 ± 1 oC). Carryoutat leasttentitrationsand calculatethemeanvaluex The concentration c, in moles of HCl per litre, of .the and the standard deviation s, using the following equations: hydrochloric acid solutionisgivenbytheequation N m1 Xi 0,107 87 V X= / = 1 N where m1 is the mass, in grams, of electrolytic silver weighed; and V, is the volume, in millilitres, of hydrochloric acid solu. (x;-x)2 tion used for the titration; Carry out ten titrations and calculate the mean value. N-- 1 w