Acetic acid, CH3COOH, contains both a methyl group and a carboxylic acid functional group. Its condensed structural formula may be written as CH3–C(O)OH, where the second carbon is doubly bonded to one oxygen and singly bonded to another oxygen (which is in turn bonded to hydrogen).
Answer the following questions regarding the distribution of partial charges in a single molecule of acetic acid.
(a) Draw a complete Lewis structure for acetic acid, including one resonance form that delocalizes charge within the carboxylate portion.
(b) On your drawing, assign δ+ and δ− symbols to every atom directly bonded to the carbon skeleton (C, H, and O atoms only). Provide one sentence of justification for each type of bond.
(c) Identify (i) the atom bearing the greatest partial positive charge and (ii) the atom bearing the greatest partial negative charge in the molecule. Explain how both electronegativity differences and resonance delocalization lead to these choices.
(d) Among all single bonds in the molecule, predict which has the largest bond dipole moment. Support your answer with quantitative or qualitative reasoning that references both ∣Δχ∣ and bond length considerations.