Question

Maximum -I effect exerted by which of the following group ?

• A. $N{O}_2^{-}$
• B. $B{r}^{-}$
• C. $N{F}_3^{+}$
• D. $C{l}^{-}$

Answer 1

The correct option is C $N{F}_3^{+}$

$N{F}_3^{+}$ has maximum electron withdrawing (-I) capacity as positive charge is present on Nitrogen atom. Hence it shows maximum -I effect.
$N{O}_2^{-}$ has more electron withdrawing capacity than halogens (Cl & Br) since N is more electronegative than Cl and Br.
More the electronegative atom, more it will have tendency to withdraw electron.
$C{l}^{-}>B{r}^{-}$
Thus the correct order of -I effect is $N{F}_3^{+}>N{O}_2^{-}>C{l}^{-}B{r}^{-}$
hence, $N{F}_3^{+}$ exert maximum -I effect.