What is the value of spin-only magnetic moment for $Cu^{2+}$ in $BM$?

The number of possible geometric isomers for a square planar complex $[Mabcd]$ is ............. ($M =$ central metal,$a, b, c, d =$ monodentate ligands).

$A$ metal complex with a formula $MCl_4 \cdot 3NH_3$ is involved in $sp^3d^2$ hybridisation. It upon reaction with excess of $AgNO_3$ solution gives '$x$' moles of $AgCl$. Consider '$x$' is equal to the number of lone pairs of electron present in the central atom of $BrF_5$. Then the number of geometrical isomers exhibited by the complex is $............$

Which complex among the following has the highest value of spin only magnetic moment?
$[Fe(CN)_6]^{3-}, [Fe(CN)_6]^{4-}, [Ni(CN)_4]^{2-}, [NiCl_4]^{2-}$

Which of the following has diamagnetic character?

Which of the following compounds can show cis-trans isomerism?