Boron halides behave as Lewis acids because of their

Identify the correct statements from the following:
$a$) Borax gives blue coloured $Co(BO_2)_2$ when heated with $Co^{2+}$ salt.
$b$) The correct formula of Borax is $Na_2[B_4O_5(OH)_4] \cdot 8H_2O$.
$c$) Trihalides of boron are Lewis bases.

The number of acidic protons in $H_{3}PO_{3}$ is:

Which elements of group $13$,except $B$,can form tetrahedral and octahedral complexes in aqueous medium?

Marine plants are an important source of which of the following?

The set of amphoteric oxides among the given oxides are $Ga_2O_3, As_4O_{10}, Sb_4O_{10}, B_2O_3, Tl_2O$.