The number of optical isomers possible for $[Cr(C_{2}O_{4})_{3}]^{3-}$ is $.....$ .

The correct order of the spin-only magnetic moments of the following complexes is
$(I) [Cr(H_2O)_6]Br_2$
$(II) Na_4[Fe(CN)_6]$
$(III) Na_3[Fe(C_2O_4)_3] (\Delta_0 > P)$
$(IV) (Et_4N)_2[CoCl_4]$

Which one of the following species responds to an external magnetic field?

The number of possible stereoisomers for the complex $[Co(en)_2Cl_2]Cl$ is $(en = \text{ethylenediamine})$.

Explain optical isomerism in six-coordinated complex compounds or octahedral complexes.

Which of the following molecules/ions can exhibit isomerism:

$A$. Tetrahedral $NiCl_2Br_2^{2-}$	$B$. Square planar $Pt(NH_3)_2Cl_2$
$C$. Octahedral $Co(NH_3)_3Cl_3$	$D$. Square planar $Pd(NH_3)_3Br^{+}$
$E$. Octahedral $Co(en)_3^{3+}$

Here,$en = 1,2-\text{diaminoethane}$.