What is the type of hybridization in $ClO_2^-$?

Among the following transformations,the hybridisation of the central atom remains unchanged in

Which of the following compounds shows the hybridization mode $sp^2 - sp^2 - sp - sp$ from left to right?

The hybridisation of $N$ in $NO_2^{+}$,$NO_3^{-}$ and $NH_4^{+}$ respectively is

Hybrid state of Aluminium in acidified aqueous solution of $AlCl_3$ is

Which is the correct statement?
As the $s$-character of a hybrid orbital decreases:
$(I)$ The bond angle decreases
$(II)$ The bond strength increases
$(III)$ The bond length increases
$(IV)$ Size of orbitals increases