Question

Among the following the strongest base is

• A. $C_6{H}_{5}N{H}_2$
• B. $p-N{O}_2{C}_6{H}_{4}N{H}_2$
• C. $m-N{O}_2{C}_6{H}_{4}N{H}_2$
• D. $C_6{H}_{5}C{H}_{2}N{H}_2$

Answer 1

The correct option is D $C_6{H}_{5}C{H}_{2}N{H}_2$

Lone pair of electrons is reponsible for the Lewis basic nature of amino group. In benzamine (d) the lone pair is free and is not taking part in resonance, and hence most basic. In other cases, lone pair of nitrogen is part of delocalisation which decreases Lewis base strength.