Reference number
ISO 2993:1974
ISO 2993:1974
© ISO 2025
International Standard
ISO 2993:1974
Ammonium sulphate for industrial use — Determination of free acidity — Titrimetric method
Edition 1
1974-04
1974-04
ISO 2993:1974
8043
Published
(Edition 1, 1974)
This publication was last reviewed and confirmed in 2019.
Therefore this version remains current.
Abstract
Applicable to products having a free acidity, expressed as H2 SO4 , equal to or more than 0.01 % (m/m). Dissolution of a test portion in Water and titration with standard volumetric sodium hydroxide solution in the presence of an indicator. The indicator must have a colour change in the pH range between 5.2 and 5.6. Has also been approved by the IUPAC.