Phosphoric acid for industrial use — Determination of sulphate content — Method by reduction and titrimetry
NORMA vydána dne 1.11.1974
Označení normy: ISO 2997:1974
Datum vydání normy: 1.11.1974
Počet stran: 3
Přibližná hmotnost: 9 g (0.02 liber)
Země: Mezinárodní technická norma
Kategorie: 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.