Carboxylic acid can be distinguished from an alcohol by performing the following tests: 
(i) Litmus Test: Take 2 ml of alcohol and a carboxylic acid in test tubes. Put 1 or 2 drop of blue litmus solution into each test tube. The liquid which show no effect is alcohol and liquid which turns red is carboxylic acid.
(ii) Sodium hydrogen carbonate test: When a solution of baking soda is treated with a few drops of a carboxylic acid, brisk effervescence is observed due to the evolution of carbon dioxide gas. When this gas is passed in lime-water, the later turns milky. Whereas no effervescence occurs upon treating an alcohol with baking soda solution.