How will you distinguish between the following isomer pairs?
(a). (i). `[Cr(NH_3)_5Br]SO_4` and (ii). `Cr(NH_3)_5(SO_4)]Br`
(b). (i). `[Co(H_2O)_6]Cl_3` and (ii) `[Co(H_2O)_5Cl]Cl_2H_2O`
(c). (i). `cis[Pt(NH_3)_2Br_2]` and (ii) trans`[Pt(NH_3)_2Br_2]`
(d). The two enantiomers of `[CrCl_2(en)_2]^(o+)`

Explanation

(a). Isomer (i) gives white ppt. Of `BaSO_4` with `BaCl_2` solution whereas isomer (ii) does not form a precipitate.
(b). The water molecule in isomer (ii) is lost easily on heating whereas the water molecule in isomer (i) are not lost easily, being coordinated to the central atom. Moreover (i) gives 3 moles of `AgCl`, (ii) gives 2 moles of `AgCl` with `AgNO_3`.
(c). cis isomer is (i) has dipole moment, the trans isomer (ii) does not.
(d). One isomer is dextrorotory whereas the other is leavorotatory.