Question 6. Option 2nd and 3rd

Asked by abhitailor158 | 7th Mar, 2019, 04:44: PM

Expert Answer:

(ii) Decreasing order of basic strength:

p- Toluidine > aniline > p- nitroaniline

This is because -NO2 group has an electron withdrawing inductive effect or -I effect and -CH3 group has electron releasing inductive effect or +I effect. Groups with -I effect decreases the electron density on the nitrogen of amino group and hence decreases the basic strength. Groups with +I effect increases the electron density on the nitrogen of amino group and hence increases the basic strength.

(iii) Increasing order of pKb value:

(C2H5)2NH < C2H5NH2 < C6H5NHCH3 < C6H5NH2

This is because -C6H5 group has an electron withdrawing inductive effect or -I effect and -C2Hgroup has electron releasing inductive effect. Groups with -I effect decreases the electron density on the nitrogen of amino group and hence decreases the basic strength. Groups with +I effect increases the electron density on the nitrogen of amino group and hence increases the basic strength. Greater the basic strength the smaller is the pKb value.

Answered by Ramandeep | 7th Mar, 2019, 06:09: PM