Most organic acids can be represented as RCOOH, in which COOH is the carboxyl group and R is the rest of the molecule. (For example, R is CH3 in acetic acid, CH3COOH.) (a) Draw the Lewis structure of acetic acid. draw structure ... (b) Upon ionization, the carboxyl group is converted to the carboxylate group, COO−. Draw the Lewis structure for one of the two resonance structures of the acetate anion. (The acetate anion is the ionized form of acetic acid). draw structure ...