See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

# Acidic Strength of Nitroalkanes **Key Principle:** Acidity of nitroalkanes depends on stabilization of the conjugate anion by electron-withdrawing groups. More $NO_2$ groups = stronger acid. **Analysis of each compound:** **(I) $CH_3-NO_2$** (nitromethane) One $NO_2$ group; moderate stability of anion **(III) $CH_3-CH_2-NO_2$** (nitroethane) One $NO_2$ group but with additional alkyl group; anion less stabilized due to electron-donating ethyl chain **(II) $NO_2-CH_2-NO_2$** (dinitromethane) Two electron-withdrawing $NO_2$ groups; strong stabilization of conjugate anion **(IV) $NO_2-CH(NO_2)-NO_2$** (trinitromethane) Three $NO_2$ groups; maximum electron-withdrawal and anion stabilization → **strongest acid** **Reasoning:** - Compound IV with three $NO_2$ groups: strongest delocalization of negative charge in conjugate anion - Compound II with two $NO_2$ groups: very strong (more acidic than I and III) - Compound I with one $NO_2$ and no electron-donating alkyl: moderate acidity - Compound III with one $NO_2$ but adjacent alkyl group: least acidic (weakest stabilization) **Order: $IV > II > I > III$** **The answer is (1) $IV > II > I > III$**