Question

Which of the following is incorrectly matched?

विकल्प

• Decreasing order of pK_b values:

  \[\ce{(C2H5)2NH > C2H5NH2 > C6H5NH2 > C6H5NHCH3}\]

• Decreasing order of basic strength:

  \[\ce{(C2H5)2NH > CH3NH2 > C6H5NHCH3 > C6H5NH2}\]

• Increasing order of basic strength:

  p-nitroaniline < aniline < p-toluidine

• Increasing order of solubility in water:

  \[\ce{C6H5NH2 < (C2H5)2 NH < C2H5NH2}\]

Answer 1

Decreasing order of pK_b values:

\[\ce{(C2H5)2NH > C2H5NH2 > C6H5NH2 > C6H5NHCH3}\]

Explanation:

\[\ce{C6H5NH2 and C6H5NHCH3}\] are less basic than \[\ce{C2H5NH2 and (C2H5)2 NH}\] it is due to the delocalisation of lone pair of electron of N-atom over the benzene ring.