Number of possible isomers for $[Cr(H_2O)_2(C_2O_4)_2]^{-}$ are . . . . . . .

The isomer$(s)$ of $[Co(NH_{3})_{4}Cl_{2}]^{+}$ that has/have a $Cl-Co-Cl$ angle of $90^{\circ}$ is/are:

Identify the homoleptic complex(es) that is/are low spin.
$(A) \ [Fe(CN)_5NO]^{2-}$
$(B) \ [CoF_6]^{3-}$
$(C) \ [Fe(CN)_6]^{4-}$
$(D) \ [Co(NH_3)_6]^{3+}$
$(E) \ [Cr(H_2O)_6]^{2+}$
Choose the correct answer from the options given below:

Which of the following are diamagnetic?
$I. K_4[Fe(CN)_6]$
$II. K_3[Cr(CN)_6]$
$III. K_3[Co(CN)_6]$
$IV. K_2[Ni(CN)_4]$
Select the correct answer using the codes given below:

Match the complex ion (in List-$I$) with the number of unpaired electrons (in List-$II$):

List-$I$	List-$II$
$A$. $[Fe(H_2O)_6]^{2+}$	$P$. $0$
$B$. $[Fe(H_2O)_6]^{3+}$	$Q$. $1$
$C$. $[Fe(CN)_6]^{4-}$	$R$. $2$
$D$. $[Fe(CN)_6]^{3-}$	$S$. $4$
$E$. $[Ni(H_2O)_4]^{2+}$	$T$. $5$

Consider the following isomerisms:
$1.$ Ionization
$2.$ Hydrate
$3.$ Linkage
$4.$ Geometrical
$5.$ Optical
Which isomerisms are exhibited by $[Cr(NH_3)_2(OH)_2Cl_2]^-$?