Given below are the statements about diborane.

$(a)$ Diborane is prepared by the oxidation of $\mathrm{NaBH}_{4}$ with $\mathrm{I}_{2}$.

$(b)$ Each boron atom is in sp $^{2}$ hybridized state.

$(c)$ Diborane has one bridged $3$ centre$-2-$electron bond.

$(d)$ Diborane is a planar molecule.

The option with correct statement(s) is :

The solubility of anhydrous $AlCl_3$ and hydrous $AlCl_3$ in diethyl ether are $S_1$ and $S_2$ respectively. Then

The element which exists in liquid state for a wide range of temperature and can be used for measuring high temperature is :- 

$B_2H_6 + 2NaH \to$ compound $'P'$ Identify the hybridisation of Boron in compound $'P'$

The liquid field metal expanding on solidification is