Total number of cis $N-Mn-Cl$ bond angles (that is,$Mn-N$ and $Mn-Cl$ bonds in cis positions) present in $cis-[Mn(en)_2Cl_2]$ is: $(en = NH_2CH_2CH_2NH_2)$

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

The number of geometrical isomers for octahedral $[CoCl_4(NH_3)_2]^-$,square planar $[AuBr_2Cl_2]^-$ and $[PtCl_2(en)]$ are

Which one of the following pairs of isomers and types of isomerism are correctly matched?
$(i).$ $[Co(NH_3)_5(NO_2)]Cl_2$ and $[Co(NH_3)_5(ONO)]Cl_2$ .... (Linkage)
$(ii).$ $[Cu(NH_3)_4][PtCl_4]$ and $[Pt(NH_3)_4][CuCl_4]$ .... (Coordination)
$(iii).$ $[PtCl_2(NH_3)_4]Br_2$ and $[PtBr_2(NH_3)_4]Cl_2$ .... (Ionization)
Select the correct answer using the codes given below.

Two soluble salts of iron $A$ & $B$,on combining with excess of a reagent $(R)$ produce compound $C$ (pale yellow) & $D$ (yellow) respectively. Reaction of $A$ with $D$ and that of $B$ with $C$ both produce a blue coloured compound. Which of the following statements is correct?

Which among the following metal complexes exhibits optical activity? ($AA$ = bidentate ligand; $A, X$ = monodentate ligands)