If the magnetic moment of $[Ag(CN)_2]^{-1}$ is zero,then the number of unpaired electrons will be

Arrange the following in the increasing order of their magnetic moments:
$I.$ $[Mn(CN)_6]^{3-}$
$II.$ $[MnCl_6]^{3-}$
$III.$ $[Fe(CN)_6]^{3-}$
$IV.$ $[FeF_6]^{3-}$

Which of the following complex ions is not expected to absorb visible light?

The correct order of the calculated spin-only magnetic moments of complexes $A$ to $D$ is:
$A$. $Ni(CO)_{4}$
$B$. $[Ni(H_{2}O)_{6}]Cl_{2}$
$C$. $Na_{2}[Ni(CN)_{4}]$
$D$. $PdCl_{2}(PPh_{3})_{2}$

Which of the following complex compounds exhibits geometrical isomerism?

Coordination isomerism could be shown by