Inductive effect

 

let us take an example.

H₃C-CH₂-Cl

 _{2          1}

 

In the above example C---C bond will have no polarity bcoz it connects two similar atoms.but this bond is polarised due to presence of Cl atom which is electronegative.

C1 will acquire a partial + charge and Cl partial --ve charge. so in order to compensate for the electron deficiency the C1 will attract the electrons of C2 towards itself and C2 will acquire ++ charge ie very small amt of +ve charge and the effect will be transmitted so on....the +ve charge magnitude getting smaller and smaller

+      +     -

H₃C--- CH₂--- Cl

 

there are 2 types of inductive effect +I AND --I.

the one discussed above is an example of --I.

 

distinction b/w +I AND --I

 when the atom attached to alkyl group is electron withdrawing ie more electronegative wrt alkyl grp, it is said to be -I. If atom attached to alkyl grp is electron donating ie less electronegative wrt alkyl grp then it is +I.

 

+I GRPS-- O^-, CO₂^- , CR₃, CHR₂, CH₂R,CH₃....

-I grps- halogens,NO₂, SO₂R,CN,COOR,OR,COR,SH,OH,NH₃⁺