Experimental studies show that the C–N bond in an amide is much less able to rotate…
CHEMISTRY · Single correct · AP · Chemistry · Compound Structure and Properties · Compound Structure and Properties
Problem
Experimental studies show that the C–N bond in an amide is much less able to rotate than a typical C–N single bond. Which statement most directly accounts for this observation?
(a) Intramolecular hydrogen bonding between the carbonyl oxygen and the amide hydrogen locks the C–N bond in place and prevents rotation.
(b) Steric repulsion between the carbonyl oxygen and the substituents on nitrogen makes rotation about the C–N bond unfavorable.
(c) Resonance delocalization gives the C–N bond partial double-bond character, greatly increasing the rotational barrier.
(d) The nitrogen in an amide is sp-hybridized, creating a linear C–N bond that cannot freely rotate.