(N/A) Definition: The permanent displacement of shared electron pairs along a carbon chain due to the presence of an atom or group with different electronegativity is called the inductive effect.
When a covalent bond is formed between atoms of different electronegativity,the electron density is shifted towards the more electronegative atom. This results in bond polarity.
$(B)$ Representation: The polar covalent bonds are denoted by the symbol $\delta$ (delta). The shift of electron density is shown by an arrow $(\rightarrow)$ that points from the less electronegative atom to the more electronegative atom.
$(C)$ Example: In chloroethane $(CH_{3}-CH_{2}-Cl)$,the $C-Cl$ bond is polar because $Cl$ is more electronegative than $C$. The electrons are shifted towards $Cl$,creating a partial positive charge $(+\delta)$ on the $C$ atom attached to $Cl$ and a partial negative charge $(-\delta)$ on $Cl$.
$(D)$ Key Characteristics:
$(i)$ Distance Dependence: The effect decreases rapidly as the distance from the source increases and is generally negligible after the third carbon atom.
$(ii)$ Additive Nature: The effect increases with the number of electron-withdrawing groups attached to the same carbon atom.
$(iii)$ Group Strength: The magnitude of the effect depends on the electronegativity of the substituent group (e.g.,$-F > -Cl > -Br > -I$).
$(E)$ Types:
$(i)$ Electron-withdrawing inductive effect ($-I$ effect): Caused by groups that attract electrons (e.g.,$-NO_{2}, -CN, -F, -Cl$).
$(ii)$ Electron-donating inductive effect ($+I$ effect): Caused by groups that release electrons (e.g.,alkyl groups like $-CH_{3}, -C_{2}H_{5}$).