The correct order of C=O bond length in ethyl | vedclass

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Question

(B) The bond length of the $C=O$ bond depends on the extent of resonance. Greater resonance character increases the single bond character of the $C=O$

Vedclass · Accepted Answer

$III > II > I$

Vedclass · Answer

(B) The bond length of the $C=O$ bond depends on the extent of resonance. Greater resonance character increases the single bond character of the $C=O$ bond, thereby increasing its bond length.$I$: Ethyl propanoate has no conjugation with the $C=O$ group.$II$: Ethyl propenoate has conjugation between the $C=C$ double bond and the $C=O$ group, which increases the single bond character of $C=O$.$III$: Ethenyl propanoate has conjugation between the lone pair of the oxygen atom and the $C=O$ group (back-bonding), which significantly increases the single bond character of $C=O$.Comparing the resonance effects:In $III$, the lone pair on the oxygen atom is directly conjugated with the $C=O$ group, leading to a strong resonance effect that makes the $C=O$ bond more like a single bond.In $II$, the $C=C$ double bond is conjugated with the $C=O$ group.In $I$, there is no such conjugation.Thus, the extent of single bond character is $III > II > I$.Therefore, the order of $C=O$ bond length is $III > II > I$.

The correct order of $C=O$ bond length in ethyl propanoate $(I)$, ethyl propenoate $(II)$ and ethenyl propanoate $(III)$ is

Similar Questions

Resonance effect is not observed in

The correct order of stability for the given canonical structures is:
$(I)$ $H-C(=O)-CH_2^-$
$(II)$ $H-C(O^-)(^+)-CH_2^-$
$(III)$ $H-C(O^-)=CH_2$

Shown below is the structure of methyl acetate with three different $\alpha, \beta$ and $\gamma$ carbon-oxygen bonds.
The correct order of bond lengths of these bonds is:

In which of the following is the first resonating structure less stable compared to the second one?

The correct stability order of the given canonical structures is:

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