ISO 3328:1975
Nitric acid for industrial use — Determination of sulphate content — Method by reduction and titrimetry
OVERVIEW
Applicable to products the SO4 content of which is equal to or more than 0.0001 % (m/m). Heating of a test portion to dryness in the presence of sodium carbonate. Reduction of the sulphureous residue to sulphides by a mixture of hydriodic acid and hypophosphorus acid. Absorption of the hydrogen sulphide evolved in a mixture of sodium hydroxide solution and acetone. Titration with standard volumetric mercury(II) acetate solution in the presence of dithizone as indicator. A typical apparatus for reduction and distillation is shown in a figure.
COMMENTS
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PRODUCT DETAILS
| Status | Withdrawn - 06 Jan 2026 |
|---|---|
| Edition | 1975 |
| No. of Pages | 4 |
| ICS Classification | 71.060.30 Acids |
| Committee | ISO/TC 47 |
| Available for Purchase | For sale in Singapore only |
| Adoption | ISO |