The correct order of hybridization of the central atom in the following species $NH_3$,$[PtCl_4]^{2-}$,$PCl_5$,and $BCl_3$ is

An aqueous solution of metal ion $M1$ reacts separately with reagents $Q$ and $R$ in excess to give tetrahedral and square planar complexes,respectively. An aqueous solution of another metal ion $M2$ always forms tetrahedral complexes with these reagents. Aqueous solution of $M2$ on reaction with reagent $S$ gives a white precipitate which dissolves in excess of $S$. The reactions are summarized in the scheme given below:
$1.$ $M1$,$Q$ and $R$,respectively are :
$(A)$ $Zn^{2+}, KCN$ and $HCl$
$(B)$ $Ni^{2+}, HCl$ and $KCN$
$(C)$ $Cd^{2+}, KCN$ and $HCl$
$(D)$ $Co^{2+}, HCl$ and $KCN$
$2.$ Reagent $S$ is :
$(A)$ $K_4[Fe(CN)_6]$
$(B)$ $Na_2HPO_4$
$(C)$ $K_2CrO_4$
$(D)$ $KOH$
Give the answer for question $1$ and $2$.

The geometry of $Ni(CO)_4$ and $[Ni(PPh_3)_2Cl_2]$ are

The octahedral diamagnetic low spin complex among the following is

Which one of the following ions is not tetrahedral in shape?

Which of the following complexes is an outer orbital complex?