JEE Main 2014 · 19 Apr · Shift 1 · Chemistry Q54

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ChemistrySingle correct+4 / -1Question 54 of 90

Which one of the following substituents at para-position is most effective in stabilizing the phenoxide ion ( $\ce{C6H5O-}$ ) ?

Phenoxide ion: a benzene ring bearing O⁻.

\ce{-CH3}

\ce{-OCH3}

\ce{-COCH3}

\ce{-CH2OH}

Answer and worked solution

Official answer: C

A para -COCH₃ group withdraws electrons by resonance and delocalises the negative charge onto its carbonyl oxygen, stabilising the phenoxide most. -CH₃, -OCH₃ and -CH₂OH are donating or only weakly withdrawing.

Topics:Phenols Electronic effects (inductive, resonance, hyperconjugation)

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JEE Main 2014 · 19 Apr · Shift 1, Chemistry question 54