Three bottles without labels contain solutions: phosphoric acid, potassium hydroxide

Three bottles without labels contain solutions: phosphoric acid, potassium hydroxide, aluminum chloride. how to prove that there is aluminum chloride in one of the flasks?

Three test tubes contain substances of different classes: acid, base (alkali), salt (aluminum chloride).

Acids and alkalis tend to change the color of the indicators. Let us put a litmus paper in three test tubes with substances. In a test tube with acid, the litmus paper will turn red, in a test tube with alkali it will turn blue, in a test tube with salt the paper will not change color.

To prove that there really is aluminum chloride in the test tube, silver nitrate can be added, – a white precipitate – aluminum chloride (silver nitrate is a high-quality reagent for chloride ions); or you can add alkali, a white precipitate is also formed – aluminum hydroxide. Reaction with hydroxide ions is a qualitative reaction to a metal (aluminum) ion.

AlCl3 + 3NaOH = Al (OH) 3 ↓ + 3NaCl.

AlCl3 + 3 AgNO3 = Al (NO3) 3 + 3 AgCl ↓.