Boron compounds act as Lewis acids due to their .....

Is boric acid a protic acid? Explain.

Which element of group $13$ does not show the group valency in its compounds?

Borax is converted into crystalline boron by the following steps:
$Borax$ $\xrightarrow{X} H_3BO_3$ $\xrightarrow{\Delta} B_2O_3$ $\xrightarrow[\Delta]{Y} B$
$X$ and $Y$ are respectively:

In the following reaction,assign the correct category for the underlined atom in the product of complete hydrolysis at $R.T.$:
$\underline{I}Cl_3 + H_2O \longrightarrow HIO_2 + HCl$

Match the following:

List-$I$ (Group $13$ element)	List-$II$ (Metallic radius,$pm$)
$A$. $Al$	$I$. $135$
$B$. $Ga$	$II$. $143$
$C$. $In$	$III$. $170$
$D$. $Tl$	$IV$. $167$

The correct answer is: