Select the correct code about complex $[Cr(NO_2)(NH_3)_5][ZnCl_4]$:
$(I)$ $IUPAC$ name of compound is pentaamminenitrito$-N$-chromium$(III)$ tetrachlorozincate$(II)$
$(II)$ It shows geometrical isomerism
$(III)$ It shows linkage isomerism
$(IV)$ It shows coordination isomerism

$[Ni(CO)_4]$ is diamagnetic. Which of the following statements is correct for this complex?

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 number of ions present in $2.0 \ L$ of a solution of $0.8 \ M \ K_4[Fe(CN)_6]$ is

Which of the following orders is not correct?

In which of the following complexes is the pairing of $(n-1)d$ electrons $NOT$ present in the presence of strong field ligands $(SFL)$?