Out of the following coordination entities,which is chiral (optically active)?

Why is geometrical isomerism not possible in tetrahedral complexes having two different types of unidentate ligands coordinated with the central metal ion?

Magnetic moment is expressed in

For an octahedral complex $MX_{4}Y_{2}$ ($M=$ a transition metal,$X$ and $Y$ are monodentate achiral ligands),the correct statement among the following is

Explain paramagnetism and diamagnetism.

For the octahedral complexes of $Fe^{3+}$ in $SCN^{-}$ (thiocyanato-$S$) and in $CN^{-}$ ligand environments,the difference between the spin-only magnetic moments in Bohr magnetons (when approximated to the nearest integer) is
[Atomic number of $Fe = 26$]