Which base among the following reacts with diborane to cleave it unsymmetrically?

What is the decreasing order of Lewis acid strength of boron halides?

$BF_3$ on hydrolysis forms:

Identify the correct statements from the following:
$(i)$ The atomic radius of $Al$ is lower than the atomic radius of $Ga$.
$(ii)$ Boron exists in many allotropic forms.
$(iii)$ The melting point of $Ga$ is lowest among the group $13$ elements.

Explain what happens when boric acid is heated.

Kernite and cryolite are the minerals of two elements $X$ and $Z$. Respectively $X$ and $Z$ are