Among the following compounds,which one is planar in shape?

Which bonds are formed by a carbon atom with $sp^{2}$-hybridisation?

Among $[I_3]^{+}$,$[SiO_4]^{4-}$,$SO_2Cl_2$,$XeF_2$,$SF_4$,$ClF_3$,$Ni(CO)_4$,$XeO_2F_2$,$[PtCl_4]^{2-}$,$XeF_4$,and $SOCl_2$,the total number of species having $sp^3$ hybridised central atom is. . . . .

The hybridisations of the atomic orbitals of nitrogen in $NO_{2}^{-}$,$NO_{2}^{+}$ and $NH_{4}^{+}$ respectively are.

The $C-C$ bond length of the following molecules is in the order:

The hybridization in sulphur dioxide is