ISO 3423-1975 rus PDF
Name in English:
St ISO 3423-1975 rus
Name in Russian:
Ст ISO 3423-1975 rus
Original standard ISO 3423-1975 rus in PDF full version. Additional info + preview on request
Full title and description
St ISO 3423-1975 — Sulphuric acid and oleums for industrial use — Determination of sulphur dioxide content — Iodometric method. This International Standard specifies an iodometric (titrimetric) procedure for measuring the sulphur dioxide (SO2) content in sulphuric acid and oleums intended for industrial use.
Abstract
The standard describes a laboratory method in which sulphur dioxide is displaced from a test portion by a stream of inert gas, absorbed into a measured volume of iodine solution, and the excess iodine is back-titrated with standardized sodium thiosulphate. The method is intended for products with SO2 content equal to or greater than 2 mg/kg. A glass absorption apparatus is illustrated and guidance on reagents, titration end-point and calculation of results is provided.
General information
- Status: Published (International Standard; confirmed on review)
- Publication date: November 1975
- Publisher: International Organization for Standardization (ISO)
- ICS / categories: 71.060.30 (Acids)
- Edition / version: Edition 1 (1975)
- Number of pages: 3
Scope
Applies to sulphuric acid and oleums for industrial use; specifies an iodometric titration method for determining the mass concentration of sulphur dioxide in these products when the SO2 content is ≥ 2 mg/kg. The procedure covers sample size, apparatus for gas displacement and absorption, required reagents, titration technique, calculation of SO2 content and reporting of results.
Key topics and requirements
- Principle: displacement of SO2 by inert gas and absorption in iodine solution; titration of excess iodine with sodium thiosulphate.
- Minimum applicable SO2 concentration: 2 mg/kg.
- Specification of glass absorption apparatus and flow conditions for effective SO2 stripping.
- Requirements for reagents (iodine solution, sodium thiosulphate standard, indicators) and their standardization.
- Calculation procedure to convert titration volumes to mass fraction or concentration of SO2.
- Precision considerations and recommended number of determinations for reporting.
- Safety and handling notes for corrosive and oxidizing reagents and for working with oleums.
Typical use and users
Used by chemical laboratories, quality control and production departments in sulphuric acid and oleum manufacturing plants, analytical service laboratories, inspection bodies, and purchasers/receivers of industrial acids for acceptance testing and specification compliance.
Related standards
Other ISO and national standards covering acids and methods for determining impurities and acidity (standards for analysis of industrial acids, iodometric and other titrimetric methods). National standards and industry-specific methods for SO2 determination in foodstuffs, raw materials and process streams may also be referenced where applicable.
Keywords
sulphuric acid; oleum; sulphur dioxide; SO2; iodometric method; titration; sodium thiosulphate; iodine; industrial acid analysis; quality control.
FAQ
Q: What is this standard?
A: ISO 3423:1975 is an international standard defining an iodometric method for determining sulphur dioxide content in sulphuric acid and oleums for industrial use.
Q: What does it cover?
A: It covers the laboratory procedure—sample preparation, apparatus for gas displacement and absorption, reagents, titration steps, calculations and reporting—applicable when SO2 content is at least 2 mg/kg.
Q: Who typically uses it?
A: Analytical chemists, QC laboratories at acid producers, inspection and testing laboratories, and procurement or regulatory bodies checking product conformity.
Q: Is it current or superseded?
A: The original ISO publication date is November 1975 (Edition 1). The document has been reviewed in subsequent ISO systematic reviews; it remains the published method as issued in 1975 and was confirmed in ISO review processes.
Q: Is it part of a series?
A: It sits among other ISO methods for acids and analytical test methods (other ISO documents addressing industrial acids, titrimetric and photometric determination methods). It is grouped under the ICS category for acids.
Q: What are the key keywords?
A: sulphuric acid, oleum, sulphur dioxide, SO2, iodometric titration, iodine, sodium thiosulphate, industrial acid analysis.