Aluminium $(III)$ chloride forms a dimer because ........

Given below are the statements about diborane.
$(a)$ Diborane is prepared by the oxidation of $NaBH_{4}$ with $I_{2}$.
$(b)$ 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 number of $2$-centre-$2$-electron and $3$-centre-$2$-electron bonds in $B_2H_6$,respectively,are

The reason for the polymeric nature of boric acid is .....

Aluminium reacts with $NaOH$ and forms compound '$X$'. If the coordination number of aluminium in '$X$' is $6$,the correct formula of $X$ is:

Which of the following properties describes the diagonal relationship between boron and silicon?