Potassium hydroxide is not unfamiliar to everyone, so what is its quality index? Next, follow Xiaobian to have a brief understanding.
1. Water insoluble substance: 5% sample solution should be colorless and transparent.
2. Lead: Take 1g sample and dissolve it in a mixture of 5ml water and 11ml dilute hydrochloric acid, then cool it. The sample solution was determined by GT-18 method. The amount of lead ion in the control solution was 10 ug.
3. Carbonate: In content analysis, 1 mol/L sulfuric acid per mL, equivalent to 138 and 2 mg of potassium carbonate, is consumed between the end point of phenolphthalein and methyl orange.
4. Heavy metals: sample 670 mg, dissolved in 5 ml water and 5 ml dilute hydrochloric acid test solution (TS-117). Heat to boil, cool, dilute to 25 ml with water, and then filter. The sample solution was determined by GT-16 method. The control solution containing 20 mg lead ion (solution A) was used.
5. Mercury: determined by CT-22 method. Standard solution and sample solution are prepared in the following way.
(1) Preparation of standard solution: According to GT-22, each storage liquid and diluent were prepared, so that the obtained solution contained 1 ug of mercury per ml. Take 1 ml of the solution and put it into a beaker of - 50 ml. Add 20 ml.1:4 dilute sulfuric acid solution 1 ml and 4% potassium permanganate solution 1 ml. Cover the beaker with a surface dish and boil for a few seconds before cooling. Set aside.
(2) Preparation of sample solution: 10.0 g of sample was put into - 100 ml beaker, 15 ml of water was added to dissolve the sample, 2 drops of TS-167 was added, and 1:1 dilute hydrochloric acid solution was used to neutralize the sample slowly under continuous stirring. Add 1:1 dilute sulfuric acid solution 1 ml and 4% potassium permanganate solution 1 ml. Cover the beaker with a surface dish, boil for a few seconds, then cool down. Set aside.
The above quality indicators of potassium hydroxide are briefly introduced here. If you have any other opinions, please feel free to call for advice.