An alcohol is a netural organic compound whereas a carboxylic acid is acidic in nature. We can distinguish between an alcohol and a carboxylic acid by using sodium hydrogencarbonate as follow.
We take the alcohol and the carboxylic acid in two separate test-tubes and add some sodium hydrogen carbonate solution of each test tube.
(a) The organic compound with produces brisk effervescence on adding sodium hydrogencarbonate due to the evolution of carbon dioxide gas will be caboxylic acid.
(b) The organic compound which has no effect on sodium hydrogencarbonate will be an alcohol.