Among (a) – (d) the complexes that can display geometrical isomerism are :
(a) [Pt(NH₃)₃Cl]⁺
(b) [Pt(NH₃)Cl₅]^–
(c) [Pt(NH₃)₂Cl(NO₂)]
(d) [Pt(NH₃)₄ClBr]²⁺

The major product in the following reaction is:

White Phosphorus on reaction with concentrated NaOH solution in an inert atmosphere of CO₂ gives phosphine and compound (X). (X) on acidification with HCl gives compound (Y). The basicity of compound (Y) is :

The radius of the second Bohr orbit, in terms of the Bohr radius, a₀, in Li²⁺ is :