Question

With reference 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

Correct option is (b) PH₃ is less basic than NH₃

The hydrides of group 15 are basic in character due to the presence of lone pair of electrons. Ammonia is strongly is basic because it can easily donate its electron pair. due to the small size of nitrogen atom. Since the electron density of lone pair is concentrated over a small region in nitrogen, NH₃​ can easily attract proton in aqueous solution. PH₃​ is weakly basic because of large size of P. the electron density around P gets diffused over a lare region and ability to attract proton decreases.