JEE Main 2026 · 6 Apr · Shift 2 · Chemistry Q63

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ChemistrySingle correct+4 / -1Question 63 of 75

Shown below is the structure of methyl acetate with three different $\alpha$ , $\beta$ and $\gamma$ carbon - oxygen bonds.

$\ce{H3C-C(=O)-O-CH3}$ , with $\alpha$ the C=O bond, $\beta$ the bond from the carbonyl carbon to the ester oxygen, and $\gamma$ the bond from that oxygen to the methyl carbon. The correct order of bond lengths of these bonds is :

\alpha>\beta>\gamma

\alpha<\beta<\gamma

\alpha=\beta=\gamma

\alpha<\beta=\gamma

Answer and worked solution

Official answer: B

Bond lengths.

α, the C=O double bond, is shortest.
β, the acyl C-O bond, has partial double-bond character from resonance with the carbonyl.
γ, the $\ce{O-CH3}$ bond, is a plain single bond and longest.

Order: $\alpha<\beta<\gamma$ .

(B)

Topics:Acid derivatives Resonance

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JEE Main 2026 · 6 Apr · Shift 2, Chemistry question 63