Potassium hydroxide will be used in many cosmetic fields, so the requirements for its quality will be relatively high when it is used. If there are many other ingredients in it, it may not achieve the expected effect when it is used. Even if it is used in cosmetics, it is harmful to the skin, So how should we determine the amount of impurities when we use it.

1、需要使用天平稱取出來準確的樣品重量在1.5-2.0g，然后放置在250ml當中的燒杯當中，并且添加進去蒸餾水將其溶解開來，等到溶解完全之后就可以導入到同等大小的容量瓶當中，并且使用水溶解到250ml的時候就可以停止添加水了。

1. First, use the balance to weigh out the accurate sample weight of 1.5-2.0g, and then place it in a beaker of 250ml, and add distilled water to dissolve it. After the dissolution is complete, it can be introduced into a volumetric flask of the same size, and the addition of water can be stopped when the water is dissolved to 250ml.

氫氧化鉀

Potassium hydroxide

2、將溶解好的溶液平均的倒入三個錐形瓶當中同樣的添加進去兩滴酚酞指示劑。然后使用鹽酸溶液滴加進去直到氫氧化鉀溶液從紅色變成了沒有顏色的時候就可以停止添加了，然后記錄下來使用過得鹽酸體積并且添加進去2滴甲基橙指示劑，同樣使用鹽酸標準溶液進行滴定知道溶液變成橙色就可以停止添加。

2. Pour the dissolved solution evenly into three conical flasks, and add two drops of phenolphthalein indicator. Then add hydrochloric acid solution drop by drop until the potassium hydroxide solution changes from red to no color. Then record the volume of hydrochloric acid used and add 2 drops of methyl orange indicator. Similarly, titrate with hydrochloric acid standard solution until the solution turns orange.

3、然后再將二次滴加的鹽酸溶液體積記錄下來，然后根據此計算出產品當中的雜質含量。

3. Then record the volume of hydrochloric acid solution added twice, and calculate the impurity content of the product according to this.

上面介紹的就是確定氫氧化鉀當中雜質含量的方法，我們在進行使用的時候一定要清楚當中所含有的雜質有哪些，還有就是會不會對我們的正常使用造成負面的影響，所以這也要求我們在進行購買的時候一定要選擇質量比較好的。

The above is the method to determine the impurity content of potassium hydroxide. When we use it, we must know what impurities it contains, and whether it will have a negative impact on our normal use. Therefore, it also requires us to choose the one with better quality when we purchase.