Identify the correct set from the following table:

Molecule	Hybridisation of central atom	Shape
$(a)$ $PCl_5$	$dsp^3$	square pyramidal
$(b)$ $[Ni(CN)_4]^{2-}$	$sp^3$	tetrahedral
$(c)$ $SF_6$	$sp^3d^2$	octahedral
$(d)$ $IF_3$	$dsp^3$	pyramidal

What is the meaning of hybridization of atomic orbitals?

The hybridization in sulphur dioxide is

Which of the following hybrid orbitals is used by the chlorine atom in the $ClO_2^-$ ion?

What is the structure of $CH_2 = C = CH_2$?

Consider the following statements for $\dot{CH_3} = X$ and $\dot{CF_3} = Y$:
$I$. When $X$ dimerises,the bond angle decreases.
$II$. When $X$ dimerises,the bond angle increases.
$III$. In the $X-Y$ molecule,the $C-C$ bond length is less than that in the $Y-Y$ molecule.
$IV$. The bond angle in $X$ is greater than that in $Y$.