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 reaction of $K_3[Fe(CN)_6]$ with freshly prepared $FeSO_4$ solution produces a dark blue precipitate called Turnbull's blue. The reaction of $K_4[Fe(CN)_6]$ with $FeSO_4$ solution in the complete absence of air produces a white precipitate $X$,which turns blue in air. Mixing the $FeSO_4$ solution with $NaNO_3$,followed by a slow addition of concentrated $H_2SO_4$ through the side of the test tube,produces a brown ring.
Precipitate $X$ is:
$(A)$ $Fe_4[Fe(CN)_6]_3$
$(B)$ $Fe[Fe(CN)_6]$
$(C)$ $K_2Fe[Fe(CN)_6]$
$(D)$ $KFe[Fe(CN)_6]$
Among the following,the brown ring is due to the formation of:
$(A)$ $[Fe(NO)_2(SO_4)_2]^{2-}$
$(B)$ $[Fe(NO)_2(H_2O)_4]^{3+}$
$(C)$ $[Fe(NO)_4(SO_4)_2]$
$(D)$ $[Fe(H_2O)_5(NO)]SO_4$

Which of the following statements is correct?

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

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

Based on the provided reaction scheme,choose the incorrect statement:
$1. \text{Metal nitrate} \xrightarrow{\Delta} A + O_2$
$2. \text{Flame test of metal nitrate} \rightarrow \text{Golden Yellow Flame}$
$3. A + \text{Thiourea} \rightarrow \text{Solution } B$
$4. \text{Solution } B + FeCl_3 \rightarrow \text{Blood red colour complex}$