See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

# Determining -I Power of Electron-Withdrawing Groups The **-I (inductive) effect** measures electron-withdrawing ability through the σ-bond framework. Stronger electron withdrawal = higher -I power. ## Analysis of Each Group: **1) $-CN$**: Cyano group - $C \equiv N$ triple bond with high electronegativity of N - Strongly withdraws electrons through σ-bonds - **Very high -I power** **2) $-NO_2$**: Nitro group - N is highly electronegative (oxidation state +5) - Directly attached N withdraws strongly - **High -I power, but slightly less than $-CN$** **3) $-NH_2$**: Amino group - N is less electronegative in reduced form - Lone pair on N actually donates electron density (+M effect dominates) - **Low -I power** (actually shows +I effect) **4) $-F$**: Fluorine - Most electronegative element - Strong -I power, but monovalent so effect localized - **Moderate -I power** ## Order of Decreasing -I Power: $$-CN > -NO_2 > -F > -NH_2$$ Which corresponds to: **(3) > (2) > (1) > (4)** ✓ **Answer: (D)** is correct because $-CN$ has the strongest inductive withdrawal, followed by $-NO_2$, then $-F$, with $-NH_2$ being the weakest (actually shows positive inductive character).