On the transformation $PCl_5 \to PCl_6^-$,what changes will take place?

The hybridisation of the central atom in $NF_3$ is:

Which of the following statements is true regarding the $PCl_5$ molecule?
$(i)$ The two axial $P-Cl$ bonds in $PCl_5$ are longer than the three equatorial bonds.
$(ii)$ The axial bonds in $PCl_5$ are stronger than equatorial bonds.
$(iii)$ The axial bonds in $PCl_5$ are more stable than equatorial bonds.
$(iv)$ All five bonds in $PCl_5$ molecule are equivalent.

The shape of the ethylene molecule is

The ammonium ion $(NH_4^+)$ is:

The hybridization states of the chlorine atom in $ClO_4^-$,$ClO_3^-$,and $ClO_2^-$ are respectively .....