Method for distinguishing sodium bicarbonate solution and sodium carbonate solution by o-cresolphthalein-alcohol solution

Abstract

The invention discloses a method for distinguishing a sodium bicarbonate solution and a sodium carbonate solution by an o-cresolphthalein-alcohol solution. The method mainly comprises the steps: taking two small test tubes, and adding 2 mL of sodium bicarbonate solution and 2 mL of sodium carbonate solution into the test tubes respectively; mixing o-cresolphthalein and an alcohol solution with the ethanol volume percentage concentration being 50 percent to prepare a colorless o-cresolphthalein-alcohol solution, wherein the volume percentage of the o-cresolphthalein to the alcohol solution is 0.05 percent; and adding 0.03 to 0.10 mL of o-cresolphthalein-alcohol solution into the two small test tubes separately, wherein the sodium bicarbonate solution does not enable the colorless o-cresolphthalein-alcohol solution to be red and the solution is still colorless, but the sodium carbonate solution enables the colorless o-cresolphthalein-alcohol solution to be red, so that the colorless sodium bicarbonate solution and the colorless sodium carbonate solution can be distinguished. The method provided by the invention is high in reliability, high in reproducibility and high in success rate; the phenomenon is obvious and full of personality; medicines and materials are easily available; the method is convenient and rapid in operation and high in safety; and the method can be applied in the technical fields of chemistry, chemical industry, medicine and the like.

Description

technical field [0001] The invention belongs to the technical fields of medicine, chemical industry and chemistry, and in particular relates to a method for discriminating sodium bicarbonate and sodium carbonate solution with o-cresolphthalein-alcohol solution. Background technique [0002] There are two types of carbonates: normal salt and acid salt. Generally, normal salt is difficult to dissolve in water, while acid salt is easy to dissolve in water. It is used to explain the formation principle of natural landscapes such as caves, stalactites and stalagmites. Affected by this principle explanation, people naturally think of using calcium chloride solution to identify sodium carbonate and sodium bicarbonate solutions. In fact, this method is not feasible, because even if the sodium bicarbonate solution with a very dilute concentration of 0.01mol / L is mixed with a calcium chloride solution of 0.01mol / L, there will be turbidity. See: ①Liu Di, Li Datang. Cannot use CaCl 2 ...

AI Technical Summary

Problems solved by technology

Obviously, although the dissociated carbonate ions of sodium bicarbonate in aqueous solution are few, they are enough to produce turbidity or even precipitation with calcium ions. Practice has proved that it is impossible to distinguish sodium carbonate and sodium bicarbonate solutions with the prior art