When ethanol reacts with excess acidified potassium dichromate (K\(_2\)Cr\(_2\)O\(_7\)), it gets oxidized to ethanoic acid (acetic acid), with the color of the solution changing from orange to green as the chromium ions are reduced during the oxidation process; this reaction is a common test for alcohols due to the visible color change. 

  CH\(_3\)CH\(_2\)OH  + K\(_2\)Cr\(_2\)O\(_7\) →  CH\(_3\)COOH