Question

Observe the following coloumn and answer the following questions. Classify the following groups as +m, -m, +I, -I, +HC, -HC.

• A. -NO₂
• B. -CN
• C. -CHO
• D. -COR
• E. -CO-
• F. -CF
• G. -CNH₂
• H. -NHCOCH₃
• I. -OCOCH₃
• J. -ONO
• K. -ONO₂
• L. -SO₃H
• M. -OSOR
• N. -SOR
• O. -Cl
• P. -Br
• Q. -I

Answer 1

The question asks to classify functional groups based on their electronic effects. The classification for each group is as follows:

• -NO₂: -I, -m
• -CN: -I, -m
• -CHO: -I, -m
• -COR: -I, -m
• -CO-: -I, -m
• -CF: -I (primarily)
• -CNH₂ (assuming -CONH₂): -I, -m
• -NHCOCH₃: +m, -I
• -OCOCH₃: +m, -I
• -ONO: -I, -m
• -ONO₂: -I, -m
• -SO₃H: -I, -m
• -OSOR: -I, -m
• -SOR: -I, -m
• -Cl: -I, +m
• -Br: -I, +m
• -I: -I, +m

Answer 2

The classification of each group is determined by its electronic structure and the nature of the atom directly attached to the pi system. Inductive effects (-I/+I) are based on electronegativity and hybridization, while mesomeric effects (-m/+m) are based on resonance delocalization of electrons. Hyperconjugation (+HC) involves delocalization of sigma electrons. Standard definitions are applied, noting that -HC is not a standard classification. Groups like -NO₂, -CN, -CHO, -COR, -CO-, -SO₃H, -SOR, -ONO, -ONO₂, -OSOR are electron-withdrawing via -I and/or -m effects. Groups like -NHCOCH₃, -OCOCH₃ exhibit +m effects due to lone pairs on N/O, alongside -I effects. Halogens (-Cl, -Br, -I) show both -I and weak +m effects, with -I dominating.