When borax is heated with $CoO$ on a platinum loop,the blue coloured bead formed is largely due to

Which reactions can be used to prepare diborane?
$I.$ $3NaBH_4 + 4BF_3 \xrightarrow{\text{ether}} 2B_2H_6 + 3NaBF_4$
$II.$ $2NaBH_4 + I_2 \to B_2H_6 + 2NaI + H_2$
$III.$ $2BF_3 + 6NaH \xrightarrow{450 \ K} B_2H_6 + 6NaF$

Draw the structure of boric acid showing hydrogen bonding. Which species is present in water? What is the hybridization of boron in this species?

Group $13$ elements show $+1$ and $+3$ oxidation states. The relative stability of the $+3$ oxidation state is given as:

The number of $2$-centre-$2$-electron and $3$-centre-$2$-electron bonds in $B_2H_6$,respectively,are

Assertion : Boron is a metalloid.
Reason : Boron shows metallic nature.