Surface active agents — Preparation of water with known calcium hardness
NORM herausgegeben am 5.4.1990
Bezeichnung normen: ISO 2174:1990-ed.3.0
Ausgabedatum normen: 5.4.1990
Zahl der Seiten: 4
Gewicht ca.: 12 g (0.03 Pfund)
Land: Internationale technische Norm
Kategorie: Technische Normen ISO
Description / Abstract: A stock solution is prepared by dissolving an appropriate quantity of calcium chloride in water. The calcium content of this stock solution is determined by complexometric titration with the disodium salt of (ethylenedinitrilo)tetraacetic acid (EDTA) using a mixture of Mordant Black 11 (C.I. 14645) and methyl red as indicator. Dilute solutions of the hardness required are prepared by dilution of appropriate volumes of the stock solution.