Multiple choice Which of the following compounds is an ester? CH3COOH CH3COCH3 CH3COOCH3 CH3CHO C2H5CHO Reveal answer Fill a bubble to check yourself C Correct answer Explanation Methyl ethanoate, i.e. CH3COO (CH3COOH) comes from ethanoic acid and CH3 comes from methanol (CH3OH). Methyl ethanoate is an ester.