The element that combines with oxygen to give an amphoteric oxide is

Identify the correct sets:
$i$. Boron fibres - bullet proof vest
$ii$. Metal borides - protective shields
$iii$. Borax - glass wool
Correct option is

Identify the $P$ and $Q$ of the following reaction: $P + Q \longrightarrow [B(OH)_4]^{-} + H_3O^{+}$

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 $....$

Which one among the following statements is correct about a solution of borax in water?

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