Identify the correct statement for $B _{2} H _{6}$ from those given below.

$(A)$ In $B _{2} H _{6}$, all $B – H$ bonds are equivalent.

$(B)$ In $B _{2} H _{6}$ there are four $3-$centre$-2-$electron bonds.

$(C)$ $B _{2} H _{6}$ is a Lewis acid.

$(D)$ $B _{2} H _{6}$ can be synthesized form both $BF _{3}$ and $NaBH _{4}$.

$(E)$ $B _{2} H _{6}$ is a planar molecule.

Choose the most appropriate answer from the options given below….. .

The incorrect stability order of $+3$ and $+1$ states of $13^{th}$ group elements (boron family) is

Give important trends and anomalous properties of boron. 

A certain salt $X,$ gives the following results.

$(i)$ Its aqueous solution is alkaline to litmus.

$(ii) $ It swells up to a glassy material $Y$ on strong heating.

$(iii)$ When conc. $H _{2} SO _{4}$ is added to a hot solution of $X,$ white crystal of an acid $Z$ separates out.

Write equations for all the above reactions and identify $X, Y$ and $Z$