Assertion : Both $Be$ and $Al$ can form complexes such as $BeF_4^{2-}$ and $AlF_6^{3-}$ respectively, $BeF_6^{3-}$ is not formed.
Reason : In case of $Be$, no vacant $d-$ orbitals are present in its outermost shell.

Give structure of gaseous $AlCl_3$. 

$BF_3$ on hydrolysis forms

Anhydrous $AlCl_3$ is formed in

Three moles of $B _2 H _6$ are completely reacted with methanol. The number of moles of boron containing product formed is