The correct decreasing order of the (electron withdrawing) effect for the given functional groups is — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

A positively charged species exerts a much stronger $-I$ effect than a neutral group. Among cations, $-NR_3^+$ has a stronger $-I$ effect than $-NH_3^+$ due to the steric expansion of the bond angle by bulky alkyl groups, increasing the s-character on the nitrogen atom. For neutral groups, the highly electronegative oxygen atoms in $-NO_2$ make it a stronger withdrawer than $-CN$.