$Na_2B_4O_7 \cdot 10H_2O \xrightarrow{\Delta} 2NaBO_2 + B_2O_3 (A) + 10H_2O$. $(A) + MnO \xrightarrow{\Delta} Mn(BO_2)_2 (B)$. $(A)$ and $(B)$ are

Sodium borohydride upon treatment with iodine produces a Lewis acid $(X)$,which on heating with ammonia produces a cyclic compound $(Y)$ and a colourless gas $(Z)$. $X, Y$ and $Z$ are $....$

$A$ 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. $H_2SO_4$ is added to a hot solution of $X$,white crystals of an acid $Z$ separate out.
Identify $X, Y$ and $Z$ and write the equations for the reactions.

What are the approximate $H-B-H$ bond angles in diborane $(B_2H_6)$?

Identify the correct statements:
$i$. Oxidation of $NaBH_4$ with $I_2$ gives $B_2H_6$
$ii$. $B_2H_6$ burns in oxygen and releases an enormous amount of energy
$iii$. $B_2H_6$ on hydrolysis gives a tribasic acid

Consider the following statements about group $13$ elements:
$A$. $AlCl_3$ achieves stability by forming a dimer.
$B$. $BCl_3$ is an electron-deficient molecule.
$C$. $E^0_{M^{3+}/M^0} \ (V)$ is $+1.26 \ V$ for aluminium.
$D$. In $+1$ oxidation state, thallium is unstable.
The incorrect statements are: