identify the optically inactive compounds among following
i. trans `-[Co(en)_(2)(NH_(3))Cl]^(2+)`
i. cis `-[Co(en)_(2)Br_(2)]^(+)`
ii. Fac `-[Co(NH_(3))_(3)Cl_(3)]`
iv. trans -`[Co[NH_(3))_(4)Cl_(2)]^(+)`
v. trans `-[CoCl_(2)(C_(2)O_(4))_(2)]^(3-)`

Answer

4

Explanation

i. trans `-[Co(en)_(2)(NH_(3))Cl]^(2+)`
iii. Fac`-[Co(NH_(3))_(3)Cl_(3)]`
iv. Trans`-[Co(NH_(3))_(4)Cl_(2)]^(+)`
v. trans `-[CoCl_(2)(C_(2)O_(4))_(2)]^(3-)`
are optically inactive due to plane of symmetry.