A laboratory report includes the following textual description of a Lewis diagram for acetic acid, CH₃COOH:
• The molecule is drawn in a straight chain: H – C – C – O – O – H.
• Each carbon is attached to enough hydrogens to give four single bonds per carbon.
• Each oxygen is shown with two lone pairs.
• No double bonds are present anywhere in the structure.
• No formal charges are indicated.
Critically evaluate the accuracy of this representation.
(a) Identify every atom in the student’s structure whose octet (or duet, where appropriate) is NOT satisfied, and briefly state why.
(b) Calculate the formal charge on each atom as the student has drawn it.
(c) Draw a fully corrected Lewis diagram for acetic acid that satisfies the octet rule where applicable and minimizes formal charges. Clearly indicate all lone pairs and any formal charges that remain.
(d) Explain, with reference to bond order and electronegativity, why the student’s omission of a C=O double bond leads to an energetically less favorable depiction of the molecule.