Question

In which of the following compounds, does the substituent not exert its resonance effect?
A. `C_(6)H_(5)overset(+)(N)H_(3)`
B. `C_(6)H_(5)Cl`
C. `C_(6)H_(5)OH`
D. `C_(6)H_(5)NH_(2)`

Answer 1

Correct Answer - A
`overset(+)NH_(3)` group exert only `-I` effect on account of higher electronegativity of `N` atom than the `C` atom of benzene ring and due to ists `+ve` charge. It is not able to exert `+R` effect as there is no long pair of electrons. It fails to exert `-R` effect beacuse `N` is not `pi` bonded to more electronegative atom.