$A$ few grams of borax is dissolved in distilled water. The $pH$ range of the resultant solution is

Orthoboric acid in aqueous medium is

Diborane reacts with $HCl$ in the presence of $AlCl_3$ and liberates:

Which of the following halides of group $13$ elements is the most acidic?

Which of the following statements about $BF_4^{-}$ and $AlF_6^{3-}$ are correct?
$(i)$ $B$ and $Al$ differ in their oxidation states.
$(ii)$ $B$ and $Al$ differ in their covalency.
$(iii)$ $B$ obeys the octet rule.
$(iv)$ $B$ and $Al$ are in diagonal relationship.

The element that has the least metallic character is ..........