Which of the following is the correct set for $SiO_2$?

The correct order of bond angle in the given species is:

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 correct order of increasing bond length of $C - H, C - O, C - C$ and $C=C$ is

Which one of the following is not correct?

The number of $S-S$ bonds in sulphur trioxide trimer $(S_3O_9)$ is