Total number of $e^-$ in $e_g$ orbitals of $Mn$ for the complex $[MnO_4]^-$ is:

Discuss the nature of bonding in the following coordination entities on the basis of valence bond theory:
$(i)$ $[Fe(CN)_6]^{4-}$
$(ii)$ $[FeF_6]^{3-}$
$(iii)$ $[Co(C_2O_4)_3]^{3-}$
$(iv)$ $[CoF_6]^{3-}$

Reaction of $[Co(H_2O)_6]^{2+}$ with excess ammonia and in the presence of oxygen results into a diamagnetic product. Number of electrons present in $t_{2g}$-orbitals of the product is $.....$ .

Consider the following test for a group-$IV$ cation.
$M^{2+} + H_2S \rightarrow A$ (Black precipitate) $+$ byproduct
$A + \text{aqua regia} \rightarrow B + NOCl + S + H_2O$
$B + KNO_2 + CH_3COOH \rightarrow C + \text{byproduct}$
The spin only magnetic moment value of the metal complex $C$ is $BM$. (Nearest integer)

Match List-$I$ with List-$II$ and select the correct answer using the codes given below the lists $:$

List-$I$ $(Compounds)$	List-$II$ $(Hybridization)$
$(a)$ $[Ni(NH_3)_6]^{+2}$	$(i)$ $sp^3 d^2$
$(b)$ $[PtCl_4]^{-2}$	$(ii)$ $dsp^2$
$(c)$ $[Ni(CO)_4]$	$(iii)$ $sp^3$
$(d)$ $[Co(OX)_3]^{-3}$	$(iv)$ $d^2 sp^3$

Which of the following hybrid states is associated with a low spin octahedral complex?