Question

Which statement is incorrect about peptide bond?

• A. $C-N$ bond length in proteins is longer than usual bond length of $C-N$ bond
• B. Spectroscopic analysis shows planar structure of $-\underset{O}{\underset{||}{C}}-NH-$ bond
• C. $C-N$ bond length in proteins is smaller than usual bond length of $C-N$ bond
• D. None of these

Answer 1

Answer: (A)

The peptide bond is a stable covalent bond and is said to be a rigid planar bond because it has a partial double bond character. The evidence that shows this partial double bond character is from the length of the bond. It is shorter than the C-N single bond yet not as short as a double bond.