1. Calculate the ratio of potassium hydroxide to water: take 30% potassium hydroxide solution as an example, then 30g potassium hydroxide and 80g water are required.

2、称取氢氧化钾和水，可用天平等相关仪器精确称取。

2. Weigh potassium hydroxide and water accurately with balance and other relevant instruments.

3、将氢氧化钾缓慢的倒入水中，用玻璃杯缓慢搅拌，直均匀。

3. Slowly pour potassium hydroxide into water and slowly stir with a glass until it is uniform.

4、标定：一般先称取定量溶液放入烘箱中烘干工作基准试剂邻苯二甲酸氢钾，再溶于无二氧化碳的水中，使用酚酞试剂进行标定。临用前标定。

4. Calibration: generally, weigh the quantitative solution first, put it into the oven and dry it until the working reference reagent potassium hydrogen phthalate is dissolved in water without carbon dioxide, and use phenolphthalein reagent for calibration. Calibration before use.

氢氧化钾标准滴定溶液的浓度，数值以摩尔每升表示，按以下公式计算：

The concentration of potassium hydroxide standard titration solution, expressed in moles per liter, is calculated according to the following formula:

其中，m——邻苯二甲酸氢钾的质量的准确数值，单位为克（g）；

Where, m -- accurate mass value of potassium hydrogen phthalate, unit: G;

V1——氢氧化钾-乙醇溶液的体积的数值，单位为毫升（ml）；

V1 -- volume of potassium hydroxide ethanol solution, unit: ml;

V2——空白试验氢氧化钾-乙醇溶液的体积的数值，单位为毫升（ml）；

V2 -- volume value of potassium hydroxide ethanol solution in blank test, unit: ml;

M——邻苯二甲酸氢钾的摩尔质量的数值，单位为克每摩尔（g/mol）[M(KHC8H4O4)=204.22]

M -- value of molar mass of potassium hydrogen phthalate, unit: g / mol [M (khc8h4o4) = 204.22]