Question

With respect to protonic acids, which of the
following statements is correct ?
(a) PH₃ is more basic than NH₃
(b) PH₃ is less basic than NH₃
(c) PH₃ is equally basic as NH₃
(d) PH₃ is amphoteric while NH₃ is basic

Answer 1

(b) The basic character decreases from NH3 to BiH3 . The basic nature is due to the presence of lone pair of electrons on the central atom. NH3 is the strongest electron pair donor due to its small size as the electron density of the electron pair is concentrated over a small region. As the size increases the electron density gets diffused over a large region and hence the ability to donate the electron pair (basic nature) decreases.