Question

Which of the following represents the decreasing order of the basicity of the hydrides of Group-15 p-block elements?

Answer 1

Answer: (D)NH3>PH3>AsH3>BiH3(D)NH3>PH3>AsH3>BiH3

Nitrogen is a small size atom; Lone pair electrons are concentrated in a small region. As we move down the group, the size of the central atom increases.

Therefore, the electron cloud diffuses over a larger volume and as a result the basic strength or the electron donor capacity decreases.