Diborane $(B_2H_6)$ reacts independently with $O_2$ and $H_2O$ to produce,respectively

Which one of the following statements is correct?

What happens when:
$(a)$ Borax is heated strongly,
$(b)$ Boric acid is added to water,
$(c)$ Aluminium is treated with dilute $NaOH$,
$(d)$ $BF_{3}$ is reacted with ammonia?

In which of the following does the inert pair effect play a significant role?

Which one of the following forms a basic oxide?

In group $13$ of the long form of the periodic table, an element $X$ has a boiling point of $T_2 \ (K)$ and a melting point of $T_1 \ (K)$. Identify the element $X$ for which $T_2 - T_1 \ (K)$ is maximum.