Question

^{Which of the following statements is incorrect about peptide bond}

• A. $C-N$ bond length in proteins is smaller than the usual bond length of $C-N$ bond.
• B. Spectroscopic analysis shows planar structure of group.
• C. $C-N$ bond length in proteins is longer than the usual bond length of $C-N$ bond.
• D. None of the above.

Answer 1

Answer: (C)

$C-N$ bond length in proteins is longer than the usual bond length of $C-N$ bond. The $C-N$ bond in the peptide has partial double bond character due to the resonance. As double bond charatcer increases bond strength increases and bond length decreases.
Spectroscopic analysis shows planar structure of group.