Which of the following reactions will yield the crystalline variety of boron?

Which of the following is the correct order of the reducing power of $Al, Ga, In,$ and $Tl$?

Three pairs of compounds are given below. Identify the compound in each pair which has the group $13$ element in a more stable oxidation state. Give reasons for your choice and state the nature of bonding. $(A)$ $TlCl_3, TlCl$ $(B)$ $AlCl_3, AlCl$ $(C)$ $InCl_3, InCl$

The structure of $Na_2[B_4O_5(OH)_4] \cdot 8H_2O$ contains:

Identify the correct statements from the following:
$a$) Borax gives blue coloured $Co(BO_2)_2$ when heated with $Co^{2+}$ salt.
$b$) The correct formula of Borax is $Na_2[B_4O_5(OH)_4] \cdot 8H_2O$.
$c$) Trihalides of boron are Lewis bases.

In diborane $(B_2H_6)$, the number of electrons that accounts for bonding in the bridges is