What substances can be used to determine that ethanol and acetic acid are in the test tubes?

To recognize in which test tube vinegar and which alcohol, it is necessary to throw a piece of metal zinc into each test tube. Zinc does not interact with ethanol, the reaction will take place only in a test tube with acetic acid: 2CH3COOH + Zn = (CH3COO) 2Zn + H2; a sign of the progress of the reaction is the evolution of gas (hydrogen). Also, using litmus paper, you can determine which test tube contains acetic acid; litmus with ethyl alcohol will not give the characteristic acidic coloration of the paper.