Potassium hydroxide is a solid product, which needs to prepare potassium hydroxide solution in some special industries. Preparation of solution is a technical activity, which requires a deep understanding of chemical products and skilled operation of experimental instruments

1、氫氧化鉀基準物經干燥處理并恒重，純度符合要求。

1. After drying and constant weight, the purity of potassium hydroxide reference material meets the requirements.

2、天平須經過檢定且處于水平狀態(tài)。

2. The balance must be calibrated and level.

3、稱取的基準物的量要準確，稱取0.27—0.33g，稱準0.0001g,基準物不能灑落稱量瓶或三角燒瓶外，影響重量。

3. The weight of the reference substance should be accurate, weighing 0.27-0.33g to 0.0001g. The reference substance should not fall outside the weighing bottle or triangular flask, affecting the weight.

4、所用蒸餾水須符合GB6682中三級水標準，煮沸10分鐘，去除CO2。

4. The distilled water used must meet the third grade water standard in gb6682, and be boiled for 10 minutes to remove CO2.

5、蒸餾水加入80ml，搖動，使其充分溶解。

5. Add 80 ml distilled water and shake to make it dissolve completely.

6、標定過程中所用量筒、三角燒瓶須潔凈干燥，量筒、滴定管經檢定。

6. The measuring cylinder and triangular flask used in the calibration process shall be clean and dry, and the measuring cylinder and burette shall be verified.

7、所用指示劑要符合要求，為10g/L酚酞指示劑，加入量要準確。

7. The indicator used should meet the requirements, be 10g / L phenolphthalein indicator, and the addition amount should be accurate.

8、滴定管要用待標定氫氧化鉀溶液清洗2—3遍，保證溶液的濃度不受影響。

8. The burette should be cleaned with potassium hydroxide solution to be calibrated for 2-3 times to ensure that the concentration of the solution is not affected.

9、溶液裝入滴定管中須無氣泡，否則影響讀數(shù)體積，手不得拿滴定管有液體位置，以免由于手溫影響體積。

9. There must be no bubbles when the solution is put into the burette, otherwise the reading volume will be affected. Do not hold the burette with liquid position, so as not to affect the volume due to hand temperature.

10、零位調整或滴定后讀數(shù)須等待30—45s?，且滴定管應垂直，視線與滴定管內液面處于同一水平位置，讀數(shù)要準確。

10. Wait 30-45s after zero adjustment or titration?, And the burette should be vertical, the line of sight and the liquid level in the burette should be in the same horizontal position, and the reading should be accurate.

11、終點顏色判斷須準確，同時作空白試驗，系統(tǒng)誤差。

11. At the same time, the blank test should be done to eliminate the systematic error.

12、滴定完畢，根據(jù)計算公式CKOH=m/［（V1-V0）*0.2042］進行計算，少取三次標定結果的算術平均值作為標準滴定溶液的實際濃度，濃度值取四位有效數(shù)字。

12. After titration, calculate according to the calculation formula ckoh = m / [(v1-v0) * 0.2042], take the arithmetic mean of at least three calibration results as the actual concentration of standard titration solution, and take four significant figures as the concentration value.

氫氧化鉀標準溶液配制后需要進行反復測量，濃度的變化對產品的性能有很大影響，因此要格外注意。

Potassium hydroxide standard solution needs to be measured repeatedly after preparation. The change of concentration has a great influence on the performance of the product, so special attention should be paid to it.