The total number of lone pairs of electrons in the given molecule is

In the trimer form of sulphur trioxide $(S_3O_9)$,each sulphur atom is bonded with:

Which of the following compounds $CANNOT$ act as a Lewis base?

Select the correct order:
$(a)$ $CO < CO_2 < CO_3^{2-}$ $\Rightarrow$ Bond length
$(b)$ $O_2 < O_3 < O_2^{2-}$ $\Rightarrow$ Bond length
$(c)$ $N_2 < N_2^+$ $\Rightarrow$ Bond energy

In which of the following,the formal charge is $NOT$ on the central atom in the most stable canonical form?

Blue vitriol contains which of the following types of bonds?