Which of the following resonance structures is the least important contributor to the resonance hybrid of the acetate anion, CH₃COO^-?

Question

Quizplus · Accepted Answer

In resonance structures, the stability of the molecule is determined by the distribution of electron density. The more stable the structure, the more it contributes to the resonance hybrid. In option C, the negative charge is located on an electronegative oxygen atom which makes it more stable than option A and B where the negative charge is on a carbon atom. Option D has an expanded octet on the central carbon atom which is less stable. Therefore, option C is the least important contributor to the resonance hybrid.

Which of the Following Resonance Structures Is the Least Important