MDCAT Chemistry MCQ #340

A student initiates an acid-catalyzed addition to propanone. What is the very first step in this mechanism to facilitate the reaction?

MDCAT Chemistry MCQ #340

  1. Question 1

    Q1. A student initiates an acid-catalyzed addition to propanone. What is the very first step in this mechanism to facilitate the reaction?

    • A) Protonation of the carbonyl oxygen atom
    • B) Deprotonation of the alpha hydrogen atom
    • C) Formation of a stable carbanion intermediate
    • D) Attack of the nucleophile on the neutral oxygen

    Answer: Protonation of the carbonyl oxygen atom

    Explanation: Protonation makes the carbonyl carbon more electrophilic for weak nucleophiles. Base catalysis is tempting but it works by strengthening the nucleophile, not carbon.