**Greater is the delocalization of the charge, greater is the stability. Electron donating groups (+I, +M and +H) hence, stabilize electron deficient species like carbocation and free-radicals. On the other hand, Electron withdrawing groups (-I and -M) hence, stabilize electron rich species i.e, carbanions.
**In a molecule having an electronegative atom joined directly to H atom, the acidity is affected by Ease of Deprotonation and Stability of conjugate base.
**Both these conditions are enhanced by introducing electron withdrawing groups (-M, -H or -I )and decreased by electron donating groups (+I, +M, +H). Remember that the second condition is more dominant one than the first to arrive to the conclusion. Hence if two are opposing, rely on the second one.
**Hence, electron donating groups (+I, +M, +H) increase the basicity; and electron withdrawing groups (-I, -M) decrease the basicity.
**An electron releasing substituent like -CH³ increases the basicity of aniline and an electron-withdrawing substituent like-X or -NO² decreases the basicity.
**Ortho/meta/para directive influence in electrophilic substitution of substituted benzene is affected by the electronic effects of the substituent.
**All ortho/para directing groups are activating except halogens. On the other hand, all electron withdrawing groups are deactivating.
ORGANIC CHEMISTRY- I (NATURE OF BONDING AND STEREOCHEMISTRY)- APPLICATIONS OF ELECTRONIC EFFECTS