Reference number
ISO 787-4:1981
© ISO 2025
International Standard
ISO 787-4:1981
General methods of test for pigments and extenders — Part 4: Determination of acidity or alkalinity of the aqueous extract
Edition 1
1981-09
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Published (Edition 1, 1981)
This publication was last reviewed and confirmed in 2024. Therefore this version remains current.

ISO 787-4:1981

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Format
CHF 43
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Abstract

The principle of the method consists in the hot extraction of the material by following the procedure specified in ISO 787/3, to the stage of obtaining a perfectly clear filtrate. The determination is carried out with indicator solution (method A). If the solution with the methyl red indicator is yellow (alkaline), titrate it with the hydrochloric acid solution to an orange end-point; if the solution with the methyl red indicator is red (acid), titrate it with the sodium or potassium hydroxide solution to an orange end-point. The other method (method B) is the potentiometric determination. Take 100 ml of the test solution, insert the electrodes of the pH measuring device and read the pH value.

General information

  • Status
     : Published
    Publication date
     : 1981-09
    Stage
    : International Standard confirmed [90.93]
  • Edition
     : 1
    Number of pages
     : 2
  • Technical Committee :
    ISO/TC 256
    ICS :
    87.060.10 
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