Which reactions can be used to prepare diborane
$I.\,\,NaBH_4 + BF_3$ (in ether) $\to $
$II.\,\, NaBH_4 + I_2 \to $
$III.\,\, BF_3 + NaH \to $
$I, \,III$
$I, \,II$
$II, \,III$
$I, \,II$ and $III$
In the extraction of aluminium, bauxite is dissolved in cryolite because
Assertion : Boron is metalloid.
Reason : Boron shows metallic nature.
In some of the reactions thallium resembles aluminium, whereas in others it resembles with group $1$ metals. Support this statement by giving some evidences.
The formation of molecular complex $BF_3 - NH_3$ results in a change in hybridization of boron
The gaseous product $(s)$ expected at room temperature by reaction of sodium borohydride and boron trifluoride under anhydrous conditions is/are: