Which one of the following oxides dissolves in both hydrochloric acid and sodium hydroxide?

Which of the following statements is incorrect?

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

Observe the following reactions (not balanced):
$BF_3 + LiAlH_4 \xrightarrow{(C_2H_5)_2O} X + LiF + AlF_3$
$X + NaH \longrightarrow Y$
The incorrect statement about $Y$ is:

The correct order of atomic radii of group $13$ elements is

$A$ 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 crystals of an acid $Z$ separate out.
Write equations for all the above reactions and identify $X, Y,$ and $Z$.