Question

(1) arrange in increasing order of solubility in water:
(Ch3)2 Nh , Ch3Nh2 , C6h5Nh2
(2) arrange in decreasing order of basic strength in aqueous solution:
(Ch3)3N , (Ch3)2Nh , Ch3Nh2
(3) arrange in increasing order of boiling point
(C2h5)2Nh , ( C2h5)3N , C2h5 Nh2

Answer 1

1) Increasing order of Solubility in Water :

  C6H5NH2 < (CH3)2NH < (CH3)NH2

2) Decreasing order of Basic strength in Aqueous solution :

    (CH3)2NH  >   CH3NH2 > (CH3)3N

3) Increasing order of Boiling point :

  (C2H5)3N  < (C2H5)2NH < (C2H5)NH2

• Due to the lone pair of Aniline is involved in conjugation with the ring, its intensity to form Hydrogen bonding decreases.
• Greater the number of Hydrogens available, greater the number of Hydrogen bonding, more will be the solubility in water.
• More solubility in water, more will be the boiling point, as more energy is required to break the bonds.
• Due to Inductive effect, Solvation effect and Steric Hinderance the basic strength in aqueous solution is effected.