GB 1254-2007Working chemical - Sodium oxalate (English PDF)

Foreword

The standard Chapter 4, 5.3.1,

5.3.2 mandatory, other provisions are recommended. This standard replaces GB 1254-1990 "work reference reagent (capacity) sodium oxalate", the main changes compared with the GB 1254-1990 as follows:

--- Standard name to "work reference reagent sodium oxalate";

--- Modify the Content Measurement (before version 4.1, this version 5.3). The standard proposed by China Petroleum and Chemical Industry Association. This standard by the National Standardization Technical Committee Chemistry Chemicals Branch (SAC/TC63/SC3) centralized. This standard is drafted by: Beijing Institute of chemical reagents. Participated in the drafting of this standard. Guangdong Guanghua Chemical Factory Co., Ltd. The main drafters of this standard. Han Baoying, strong Jing Lin, Wang Yuhua, Chenhan Zhao. This standard was first published in 1977, in 1990 the first amendment. Working Standard reagent sodium oxalate Molecular formula. Na2C2O

1 Scope

China's mandatory national standard for sodium oxalate as a working chemical. Sodium oxalate is the reducing counterpart of potassium dichromate: it is what standardises permanganate solutions, and permanganate is the workhorse oxidant of volumetric analysis, used for iron, calcium, hydrogen peroxide and chemical oxygen demand. It holds that position because it can be dried to constant weight without decomposing and its reaction with permanganate in hot acid is clean and complete - though it is famously slow to start, which is why the titration is run warm and why the first drops of permanganate seem to do nothing until the manganous ion produced begins to catalyse the reaction. The standard specifies the requirements, the impurity limits, the drying conditions and the test methods for the working grade.

This standard specifies the operating reference reagent

--- sodium oxalate traits, specifications, testing, packaging and inspection rules and signs. This standard applies to the reference reagent titration analysis work

--- sodium oxalate test.

2 Normative references

The following documents contain provisions which, through reference in this standard and become the standard terms. For dated references, subsequent Amendments (not including errata content) or revisions do not apply to this standard, however, encourage the parties to the agreement are based on research Whether the latest versions of these documents. For undated reference documents, the latest versions apply to this standard. Preparation of

GB/T 601 chemical reagent standard titration solution

GB/T 602 Determination of impurities in chemical reagents prepared standard solution ( GB/T 602-2002,

ISO 6353-1. 1982, NEQ) with

GB/T 603 chemical reagent test method Preparations of articles ( GB/T 603-2002,

ISO 6353-1 with. 1982, NEQ)

GB/T 609 chemical reagent - General method for determination of total nitrogen ( GB/T 609-2006, ISO 6353-1. 1982, NEQ)

GB/T 6682 analytical laboratory use specifications and test methods ( GB/T 6682-1992, neq ISO 3696. 1987)

GB/T 9723-2007 Chemicals flame atomic absorption spectrometry General

GB/T 9724 General rule for determination of pH chemical reagent ( GB/T 9724-2007, ISO 6353-1. 1982, NEQ)

GB/T 9728 General method for determination of chemical reagents sulfate ( GB/T 9728-2007, ISO 6353-1. 1982, NEQ)

GB/T 9737 Determination of chemical reagents easily carbonized substances General ( GB/T 9737-1988, eqv ISO 6353-1. 1982)

GB 10738 Job reference reagent titration Determination General Weighing

GB 15346 chemical reagent packaging and marking

3 Characters

This reagent is a white crystalline powder, soluble in water, soluble in ethanol.

4 Specification

Sodium oxalate as shown in Table 1. Table 1 specifications of sodium oxalate Name reference work Content (Na2C2O4), /% 99.95 ~ 100.05 pH value (30g/L, 25 °C) 7.5 ~

5 Test

5.1 Warning Reagents used in this test method are toxic or corrosive, some of the testing process can lead to dangerous situations, the operator should take Appropriate safety and health practices.

5.2 General Provisions Unless specified otherwise in this chapter, the use of standard titration solution, standard solution, preparations and products, according to GB/T 601, GB/T 602, Regulations preparation, test water should be consistent with GB/T 6682 specifications in three water samples according to precise weighing 0.01g, the use of GB/T 603's Solution "%" are represented by the mass fraction.

5.3 Content Measured according to GB 10738 requirements.

5.3.1 standard titration solution of potassium permanganate titration standard substance sodium oxalate Weigh 0.2g to (105 ± 2) °C dried to a constant standard substance sodium oxalate and precise to 0.00001g. Placed in a reaction flask, dissolved in 100mL sulfuric acid solution (80mL/L), titration with potassium permanganate standard solution [Ba (15KMnO4 ) = 0.1mol/L] titration, plus near the end point Heat to 65 °C, continue titration until the solution was pink, and maintain 30s. Weighing potassium permanganate standard titration solution should be accurate to 0.0001g. Determination