Phosphoric acid for industrial use — Determination of sulphate content — Method by reduction and titrimetry
NORMA vydaná dňa 1.11.1974
Označenie normy: ISO 2997:1974
Dátum vydania normy: 1.11.1974
Počet strán: 3
Približná hmotnosť: 9 g (0.02 libier)
Krajina: Medzinárodná technická norma
Kategória: Technické normy ISO
Description / Abstract: Applicable to products having sulphate contents equal to or more than 0.0005 % (m/m). Analysis by reduction of the sulphate to sulphide by a mixture of hydriodic acid and hypophosphorus acid. Absorption of the hydrogen sulphide evolved in a mixture of acetone and sodium hydroxide solution. Titration with a standard volumetric solution of mercury(II) acetate in the presence of dithizone as indicator. Has also been approved by the IUPAC.