Calibration method of potassium dichromate standard solution

A standard solution, potassium dichromate technology, applied in chemical method analysis, chemical analysis using titration method, measuring device and other directions, can solve the problems of uncertain concentration of potassium dichromate standard solution, high preparation cost, etc. Master and calibrate accurate results

Inactive Publication Date: 2019-04-05
JIUJIANG PINGGANG STEEL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Because the sodium thiosulfate standard solution preparation must be placed for two weeks before use, the concentration of sodium thiosulfate needs to be calibrated with the potassium dichromate standard solution of the corresponding concentration, which will increase the uncertainty of the potassium dichromate standard solution concentration; The preparation cost of potassium dichromate standard reagent is relatively high, and generally it is prepared with potassium dichromate analytical reagent and then calibrated

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  • Calibration method of potassium dichromate standard solution
  • Calibration method of potassium dichromate standard solution
  • Calibration method of potassium dichromate standard solution

Examples

Experimental program
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Effect test

Embodiment 1

[0047] Embodiment one: calibration potassium dichromate standard solution molar concentration 0.02000mol / L:

[0048] 1. Weigh 0.04000±0.0001g of pure iron (content above 99.95%) into a 500mL Erlenmeyer flask, slowly add 20-30mL of concentrated hydrochloric acid, and dropwise add 1mL of concentrated nitric acid;

[0049] 2. Boil at low temperature on a 300°C electric heating plate to remove nitrogen oxides. During the dissolution process, continuously add 6% stannous chloride solution and a certain amount of 1:1 hydrochloric acid to keep the solution slightly yellow, and the concentrated volume is about 20mL;

[0050] 3. The sample is completely dissolved and there are big bubbles, take it out and cool it down slightly;

[0051] 4. Add about 100mL of water, 1mL of 25% sodium tungstate solution, and dropwise add titanium trichloride solution 1:19 under constant shaking until the solution turns blue;

[0052] 5. Add the diluted potassium dichromate standard solution dropwise unt...

Embodiment 2

[0061] Embodiment two: calibration potassium dichromate standard solution molar concentration 0.05000mol / L:

[0062] 1. Weigh 0.1000±0.0001g of pure iron (content above 99.95%) into a 500mL Erlenmeyer flask, slowly add 20-30mL of concentrated hydrochloric acid, and dropwise add 1mL of concentrated nitric acid;

[0063] 2. Boil at low temperature on a 300°C electric heating plate to remove nitrogen oxides. During the dissolution process, continuously add 6% stannous chloride solution and a certain amount of 1:1 hydrochloric acid to keep the solution slightly yellow, and the concentrated volume is about 20mL;

[0064] 3. The sample is completely dissolved and there are big bubbles, take it out and cool it down slightly;

[0065] 4. Add about 100mL of water, 1mL of 25% sodium tungstate solution, and dropwise add titanium trichloride solution 1:19 under constant shaking until the solution turns blue;

[0066] 5. Add the diluted potassium dichromate standard solution dropwise unti...

Embodiment 3

[0074] Embodiment three: calibration potassium dichromate standard solution molar concentration 0.1000mol / L:

[0075] 1. Weigh 0.2000±0.0001g of pure iron (content above 99.95%) into a 500mL Erlenmeyer flask, slowly add 20-30mL of concentrated hydrochloric acid, and dropwise add 1mL of concentrated nitric acid;

[0076] 2. Boil at low temperature on a 300°C electric heating plate to remove nitrogen oxides. During the dissolution process, continuously add 6% stannous chloride solution and a certain amount of 1:1 hydrochloric acid to keep the solution slightly yellow, and the concentrated volume is about 20mL;

[0077] 3. The sample is completely dissolved and there are big bubbles, take it out and cool it down slightly;

[0078] 4. Add about 100mL of water, 1mL of 25% sodium tungstate solution, and dropwise add titanium trichloride solution 1:19 under constant shaking until the solution turns blue;

[0079] 5. Add the diluted potassium dichromate standard solution dropwise unt...

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Abstract

The invention discloses a calibration method of a potassium dichromate standard solution. The calibration method comprises the following steps that S1, a pure iron sample is weighed and is placed in aconical flask, hydrochloric acid and concentrated nitric acid are added slowly; S2, the conical flask is boiled at low temperature, a stannous chloride solution and the hydrochloric acid are continuously added dropwise; S3, the conical flasks cools; S4, water and a sodium tungstate dihydrate solution are added in the conical flask, and a titanium trichloride solution is added dropwise; S5, the standard solution is added dropwise in the conical flask until blue disappears, sulphuric acid-phosphoric acid mixed acid is added immediately, and a diphenylaminesulfonic acid sodium salt indicator solution are added; S6, the potassium dichromate standard solution is titrated into the conical flask until the solution in the conical flask turns into blue-green from green, when the last drop shows astable purple, titration is completed, and the volume V of the potassium dichromate standard solution consumed by titration is recorded; and S7, according to the addition quantity, molar concentrationof the potassium dichromate standard solution can be calculated. The method is accurate in calibration, and is simple and easy to master.

Description

technical field [0001] The invention relates to the technical field of potassium dichromate standard solution, in particular to a method for standardizing potassium dichromate standard solution. Background technique [0002] Potassium dichromate standard solution is a kind of standard titration solution in metallurgical chemical analysis, is commonly used in the titration of oxidation-reduction reaction, and the calculation of analysis result needs to know the accurate concentration of potassium dichromate, otherwise it will cause analysis result to deviate greatly. There are two methods for the preparation and calibration of potassium dichromate standard solution according to the national standard GB / T601-2002: [0003] 1. Weigh 5g of potassium dichromate of analytical grade, dissolve it in 1000mL of water, and shake well. Calibration of potassium dichromate standard: Measure 35.00mL-40.00mL of prepared potassium dichromate solution, put it in an iodine measuring bottle, a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N31/16
CPCG01N31/162
Inventor 周春霞李波彭陈周红霞范玲丽
Owner JIUJIANG PINGGANG STEEL
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