Discuss the dimerisation of nitrogen dioxide.

The total number of compounds having at least one bridging oxo group among the molecules given below is
${\mathrm{N}}_2{\mathrm{O}}_5, {\mathrm{P}}_4{\mathrm{O}}_6, {\mathrm{P}}_4{\mathrm{O}}_8, {\mathrm{H}}_4{\mathrm{P}}_2{\mathrm{O}}_5, {\mathrm{H}}_5{\mathrm{P}}_3{\mathrm{O}}_{10}, {\mathrm{H}}_2{\mathrm{S}}_2{\mathrm{O}}_3, {\mathrm{H}}_2{\mathrm{S}}_2{\mathrm{O}}_5$

Draw the structure of ${\mathrm{N}}_2{\mathrm{O}}_5$.

The number of bridged oxygen atoms present in compound $\mathrm{B}$ formed from the following reactions is

$\mathrm{Pb}{\left({\mathrm{NO}}_3\right)}_2\stackrel{673 \mathrm{K}}{⟶}\mathrm{A}+\mathrm{PbO}+{\mathrm{O}}_2$

$\mathrm{A}\stackrel{\mathrm{Dimerise}}{⟶}\mathrm{B}$