Give the correct increasing order of electrical conductivity of aqueous solutions of following complex entities
I) [Pt(NH₃)₆]Cl₄ 
II) [Cr(NH₃)₆]Cl₃
III) [Co(NH₃)₄Cl₂]Cl 
IV) K₂[PtCl₆]

The correct option is A, III < IV < II < I
The following complexes ionize in water to give ions as:
(i) [Pt(NH₃)₄]Cl₄→ 5 ions
(ii) [Cr(NH₃)₆]Cl₃→ 4 ions
(iii) [CO(NH₃)₄Cl₂]Cl→ 2 ions
(iv) K₂[PtCl₆]→ 3 ions
Greater the number of ions, more will be the electrical conductivity of aqueous solution of the corresponding complex.