ISO 3241-1975 rus PDF

Full title and description

ISO 3241:1975 — Sodium sulphate for industrial use — Measurement of pH — Potentiometric method. Specifies a potentiometric procedure for measuring the pH of a 10 g/l solution of sodium sulfate at 20 °C using a glass measuring electrode and a calomel reference electrode; calibration at (20 ± 1) °C and a required sensitivity of 0.05 pH unit.

Abstract

This short International Standard defines preparation of a 10 g/l sodium sulfate solution and the potentiometric method for pH measurement: apparatus (pH‑meter with glass measuring electrode and calomel reference), calibration procedure using buffer solutions at 20 °C and measurement accuracy (sensitivity 0.05 pH unit). The document is a concise, 2‑page procedural standard intended for laboratory and quality‑control use.

General information

• Status: Withdrawn (withdrawal of the International Standard).
• Publication date: June 1975 (1st edition).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 71.060.50 (Salts).
• Edition / version: Edition 1 (1975).
• Number of pages: 2.

Scope

Defines a potentiometric method to determine the pH of sodium sulfate for industrial use by preparing a 10 g/l aqueous solution and measuring its pH at 20 °C. The procedure covers required apparatus (pH‑meter with glass measuring electrode and calomel reference electrode), calibration of the instrument at (20 ± 1) °C with standard buffer solutions and the performance sensitivity (0.05 pH unit). The standard is procedural and intended for analytical laboratories and quality control of industrial sodium sulfate.

Key topics and requirements

• Preparation of test solution: dissolve sodium sulfate to make a 10 g/l solution (specified preparation steps in the standard).
• Measurement temperature: measurements and calibration specified at 20 °C (calibration at 20 ± 1 °C).
• Instrumentation: pH‑meter fitted with a glass measuring electrode and a calomel reference electrode.
• Calibration: use of certified buffer solutions for calibration; instrument sensitivity requirement 0.05 pH unit.
• Analytical quality: use of analytical‑grade reagents and recently boiled/cooled or equivalently pure water for solution preparation (general laboratory practice referenced in the procedure).

Typical use and users

Analytical and industrial chemistry laboratories, manufacturers and suppliers of sodium sulfate, QC/QA personnel in chemical production, and conformity assessment bodies that historically relied on ISO chemical test procedures. Because the standard is short and procedural, it is primarily used where a simple, reproducible pH measurement protocol for sodium sulfate is required.

Related standards

This standard is part of a group of ISO methods for sodium sulfate and related salts (examples: ISO 3236–3240 family of 1975 standards covering chloride, sulphate, calcium, iron determinations and acidity/alkalinity), many of which have been withdrawn. For committee context see ISO/TC 47 (Chemistry) and the ICS category for salts.

Keywords

sodium sulphate; sodium sulfate; pH measurement; potentiometric method; pH‑meter; calomel electrode; 10 g/l solution; 20 °C; ISO 3241:1975; analytical procedure.

FAQ

Q: What is this standard?

A: ISO 3241:1975 is an International Standard that specifies a potentiometric method for measuring the pH of a 10 g/l solution of sodium sulfate for industrial use.

Q: What does it cover?

A: It covers preparation of the test solution, required apparatus (pH‑meter with glass measuring electrode and calomel reference electrode), calibration at (20 ± 1) °C with buffer solutions, and a sensitivity requirement of 0.05 pH unit.

Q: Who typically uses it?

A: Analytical laboratories, manufacturers and suppliers of sodium sulfate, and quality control personnel in chemical production—any users needing a standardized pH measurement procedure for sodium sulfate.

Q: Is it current or superseded?

A: ISO 3241:1975 has been withdrawn (the ISO catalogue lists it in the withdrawal stage). Some catalogues and standards services indicate it was withdrawn without replacement; users should consult current national or ISO chemistry methods for up‑to‑date procedures.

Q: Is it part of a series?

A: Yes — it was issued alongside other 1970s ISO methods for sodium sulfate and related salts (e.g., ISO 3236–3240 family) developed under ISO/TC 47 (Chemistry). Many of those companion documents are also listed as withdrawn.

Q: What are the key keywords?

A: Sodium sulphate, pH, potentiometric method, pH‑meter, calomel electrode, 10 g/l, 20 °C, analytical procedure, ISO 3241:1975.