$CuSO_{4(aq)} + 4NH_3 \rightarrow X,$ then $X$ is

List-$I$ contains metal species and List-$II$ contains their properties.

List-$I$	List-$II$
$I$. $[Cr(CN)_6]^{4-}$	$P$. $t_{2g}$ orbitals contain $4$ electrons
$II$. $[RuCl_6]^{2-}$	$Q$. $\mu$ (spin-only) $= 4.9 \ BM$
$III$. $[Cr(H_2O)_6]^{2+}$	$R$. low spin complex ion
$IV$. $[Fe(H_2O)_6]^{2+}$	$S$. metal ion in $4+$ oxidation state
	$T$. $d^4$ species

[Given: Atomic number of $Cr = 24, Ru = 44, Fe = 26$] Match each metal species in List-$I$ with their properties in List-$II$,and choose the correct option.

Identify the geometrical isomers of the following complexes:

The sum of the total number of $Cr-O$ bonds in chromate $(CrO_4^{2-})$ and dichromate $(Cr_2O_7^{2-})$ ions is:

When potassium iodide is added to an aqueous solution of potassium ferricyanide,a reversible reaction is observed in which a complex $P$ is formed. In a strong acidic medium,the equilibrium shifts completely towards $P$. Addition of zinc chloride to $P$ in a slightly acidic medium results in a sparingly soluble complex $Q$.
$(1)$ The number of moles of potassium iodide required to produce two moles of $P$ is. . .
$(2)$ The number of zinc ions present in the molecular formula of $Q$ is. . . .
Give the answer for $(1)$ and $(2)$.

The magnetic moment (spin only) of an octahedral complex having $CFSE = -0.8 \Delta_0$ and surrounded by weak field ligands can be: