Which of the following transition metals is used as a catalyst?

Which of the comparison regarding $Zn, Cd, Hg$ is/are incorrect?
$(I)$ $ZnCl_2$ is ionic whereas $CdCl_2$ and $HgCl_2$ are covalent
$(II)$ $Zn$ and $Cd$ dissolve in dilute acid $(HCl)$ liberating $H_2$ but $Hg$ cannot
$(III)$ $Zn$ and $Cd$ form white ppt. of $Zn(OH)_2$ and $Cd(OH)_2$ but $Hg$ forms coloured ppt. of $HgO$ or $Hg(OH)_2$
$(IV)$ All form $M_2^{2+}$ type ion

Identify the correct statement$(s)$ among the following.

Identify the correct option:
$(I)\ AgCl$ is not soluble in $H_2O$ but soluble in $KCN$.
$(II)\ Zn$ when reacts with cold v.v. dil $HNO_3$ gives $NH_4NO_3$.
$(III)\ CuSO_4$ reacts with $KI$ to form $Cu_2I_2 + K_2SO_4$.
$(IV)\ CuSO_4 \cdot 5H_2O \xrightarrow{1000\,^oC}$ The gases liberated are $SO_2$ and $O_2$.

Which of the following have the same number of unpaired electrons in $d$ orbitals?

Given below are two statements:
Statement $I$: Iron$(III)$ catalyst,acidified $K_{2}Cr_{2}O_{7}$ and neutral $KMnO_{4}$ have the ability to oxidise $I^{-}$ to $I_{2}$ independently.
Statement $II$: Manganate ion is paramagnetic in nature and involves $p\pi-p\pi$ bonding.
In the light of the above statements,choose the correct answer from the options.