Which one of the following will not show geometrical isomerism?

Which of the following complexes or complex ions can have an optically active isomer?

$[Co(NH_3)_5Br]SO_4$ and $[Co(NH_3)_5SO_4]Br$ are examples of which type of isomerism?

$26.7 \ g$ of a compound with the formula $PtCl_2Br_2 \cdot 6H_2O$ is taken for analysis. This compound exhibits stereoisomerism,and a total of $3$ stereoisomers exist. Find the loss in mass (in $g$) when the given amount of the compound is treated with concentrated $H_2SO_4$. (Molar mass: $PtCl_2Br_2 \cdot 6H_2O = 534 \ g \ mol^{-1}$)

Match List-$I$ with List-$II$ :

List-$I$	List-$II$
$(a).$ $[Co(NH_3)_6][Cr(CN)_6]$	$(i).$ Linkage isomerism
$(b).$ $[Co(NH_3)_3(NO_2)_3]$	$(ii).$ Solvate isomerism
$(c).$ $[Cr(H_2O)_6]Cl_3$	$(iii).$ Coordination isomerism
$(d).$ $cis-[CrCl_2(ox)_2]^{3-}$	$(iv).$ Optical isomerism

Choose the correct answer from the options given below:

Which of the following predictions is correct when a transition metal ion is colourless?