When $Al$ is added to $KOH$ solution,what happens?

Which of the following is added to borax to obtain boric acid?

The correct order of Lewis acidity for $BX_3$ is:

In the reactions $I$ and $II$,the covalencies of $Be$ and $Al$ in $X$ and $Y$ are respectively:
$I$ $Be(OH)_2 + NaOH \text{ (excess)} \rightarrow X$
$II$ $Al(OH)_3 + NaOH \text{ (excess)} \rightarrow Y$

Borax is used as a cleansing agent because on dissolving in water it gives:

In the following sets of reactants,which two sets best exhibit the amphoteric character of $Al_2O_3 \cdot xH_2O$?
Set $1$: $Al_2O_3 \cdot xH_2O_{(s)}$ and $OH^{-}_{(aq)}$
Set $2$: $Al_2O_3 \cdot xH_2O_{(s)}$ and $H_2O_{(l)}$
Set $3$: $Al_2O_3 \cdot xH_2O_{(s)}$ and $H^{+}_{(aq)}$
Set $4$: $Al_2O_3 \cdot xH_2O_{(s)}$ and $NH_{3(aq)}$