Recently, a colleague asked, "how to prepare a certain concentration of basic ethanol / methanol? How to prepare a certain concentration of potassium hydroxide ethanol / methanol solution? How to prepare potassium hydroxide titrant from ethanol. In fact, several problems can be summed up as "how to prepare potassium hydroxide titrant with a certain concentration of ethanol?", After understanding this point, the preparation method similar to alkali alcohol solution can be easily done.
Potassium hydroxide manufacturers now share the preparation and calibration methods of potassium hydroxide titrant (0.5mol/l or 0.lmol/l) made from ethanol and potassium hydroxide titrant (0.lmol/l) made from methanol.
According to the preparation process introduced by the potassium hydroxide manufacturer, the amount of potassium hydroxide used in the preparation process is slightly larger than the theoretical amount. The reason for this is that the solubility of potassium hydroxide itself in ethanol is very high, but potassium hydroxide will absorb carbon dioxide in the air, and the water absorption capacity of potassium hydroxide is also very strong, Moreover, the prepared alkali alcohol solution will also absorb the air and carbon dioxide in the solution and consume the alkali in the solution.
Based on the above considerations, more potassium hydroxide should be weighed in the preparation process to achieve the required alkali concentration, but it is difficult to prepare the specific concentration directionally. Therefore, the alkali alcohol solution prepared by potassium hydroxide manufacturers should calibrate the concentration before use, and then obtain the specific alkali concentration through conversion.