See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

# Analysis of Hydroxylic Proton Acidity **Key Principle:** The acidity of a hydroxyl proton ($-OH$) increases when the conjugate base (alkoxide, $-O^-$) is stabilized through electron-withdrawing effects. **Evaluating Each Option:** **(A) $-OH$ with F attached to adjacent carbon:** - F is weakly electron-withdrawing at one position removed - Moderate stabilization of the conjugate base **(B) $-OH$ with I attached to adjacent carbon:** - I is electron-donating (poor electronegativity) - Destabilizes the conjugate base - **Least acidic** **(C) $-OH$ with F attached to adjacent carbon (branched):** - Single F substituent at one position - F effect limited to immediate vicinity **(D) $-OH$ with F attached to adjacent carbon (branched):** - **Two F atoms** present on the carbon adjacent to $-OH$ - Both F atoms withdrawal electron density inductively - **Maximum stabilization** of the conjugate alkoxide ion - Strongest cumulative electron-withdrawing effect $$\text{Acidity: B} < \text{A} < \text{C} < \boxed{\text{D}}$$ **Answer: (D)** — The presence of two fluorine atoms ortho to the hydroxyl group provides the strongest electron-withdrawing inductive effect, maximally stabilizing the conjugate base and making the hydroxylic proton most acidic.