The reason for boric acid being polymeric is .....

Select the correct statements for diborane $(B_2H_6)$:
$1.$ Boron is approximately $sp^3$ hybridized.
$2.$ The $H-B-H$ bridge angle is $180^o$.
$3.$ There are two terminal $B-H$ bonds for each boron atom.
$4.$ There are only $12$ bonding electrons available.

$AlF_3$ is soluble in $HF$ only in the presence of $KF$ due to the formation of:

Which one of the following is the correct statement?

$Na_2B_4O_7 \cdot 10H_2O \xrightarrow{\Delta} X + NaBO_2 + H_2O$
$X + Cr_2O_3 \xrightarrow{\Delta} Y$ (Green coloured)
$X$ and $Y$ are

Boric acid,$H_3BO_3$,is a/an ....