Question

The molecule is N-phenylcyclohexanecarboxamide. $\text{Ph-C-NH-}$ (A) This molecule shows geometrical isomerism. (B) One of the resonating structure of this molecule shows geometrical isomerism (C) One of the tautomer of this molecule shows geometrical isomerism (D) In acidic medium this molecule shows geometrical isomerism.

• A. This molecule shows geometrical isomerism.
• B. One of the resonating structure of this molecule shows geometrical isomerism
• C. One of the tautomer of this molecule shows geometrical isomerism
• D. In acidic medium this molecule shows geometrical isomerism.

Answer 1

Answer: (A), (B), (D)

A, B, D

Answer 2

The C-N bond in amides has partial double bond character due to resonance. This restricted rotation allows for geometrical isomerism (A). One of the resonance structures, where the C-N bond is a double bond, also exhibits geometrical isomerism (B). In acidic medium, protonation can enhance the C=N⁺ character, leading to geometrical isomerism (D). While tautomerism to imidic acids can occur, the imidic acid form is generally less stable and less likely to be the primary reason for isomerism in this context.