Which of the following types of hybridization occurs in diborane $(B_2H_6)$?

Which of the following statements is correct?

Inorganic graphite is:

Which statement is correct for $B_2H_6$?

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.

Explain the physical characteristics of group $13$ elements.