Identify the reaction which does not liberate hydrogen

Identify the correct statement for ${\mathrm{B}}_2{\mathrm{H}}_6$ from those given below.

(A) In ${\mathrm{B}}_2{\mathrm{H}}_6$, all $\mathrm{B}-\mathrm{H}$ bonds are equivalent.

(B) In ${\mathrm{B}}_2{\mathrm{H}}_6$, there are four $3$-centre- $2$-electron bonds.

(C) ${\mathrm{B}}_2{\mathrm{H}}_6$ is a Lewis acid.

(D) ${\mathrm{B}}_2{\mathrm{H}}_6$ can be synthesized from both ${\mathrm{BF}}_3$ and ${\mathrm{NaBH}}_4$.

(E) ${\mathrm{B}}_2{\mathrm{H}}_6$ is a planar molecule.

Choose the most appropriate answer from the options given below :

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

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

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