Number of molecules from the following which are exceptions to the octet rule is. . . .
$CO_2, NO_2, H_2SO_4, BF_3, CH_4, SiF_4, ClO_2, PCl_5, BeF_2, C_2H_6, CHCl_3, CBr_4$

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 .......... .

Which of the following consists of an equal number of $p\pi - p\pi$ and $p\pi - d\pi$ bonds?

Which one of the following conversions involves a change in both hybridisation and shape?

The different types of bonds present in $CuSO_4 \cdot 5 H_2 O$ are

The angular shape of the ozone molecule consists of