In solid state,$PCl_5$ is a/an

Fill in the blanks:
$(i)$ In $1927$,Heitler and London proposed the ........ theory.
$(ii)$ The ${\rm{ClF}}_3$ molecule has a .... shape.
$(iii)$ The number of bonding pairs in ions with a square planar shape is .......... .
$(iv)$ The value of the dipole moment in ${\rm{HBr}}$ is .......... .

The number of $\sigma$ bonds,$\pi$ bonds and lone pair of electrons in pyridine,respectively are:

Compound $X$ is the anhydride of sulphuric acid. The number of $\sigma$ bonds and the number of $\pi$ bonds present in $X$ are respectively:

The name of $K_2CS_3$ is potassium ............... .

Which one of the following is different from others with respect to hydrolysis?