Tubes A and B contain lime water and sodium hydroxide solution.

Tubes A and B contain lime water and sodium hydroxide solution. What qualitative reactions are required to determine the contents of each of the tubes?

Take samples from each tube. Add 1-2 drops of phenolphthalein indicator to each. Those 2 samples where the color of the solution changed from colorless to raspberry contains alkali. This means that the remaining test tube contains nitric acid. Next, we will blow for some time through the tube into the alkali samples. Where we notice the turbidity of the solution, there was lime water, which means that in the other there was caustic potassium.