Which of the following element$(s)$ exist in the liquid state?

Aluminium $(III)$ chloride forms a dimer because ........

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.

Which of the following sublimes on heating?

Hydrolysis of $BCl_3$ gives $X$,which on treatment with sodium carbonate produces $Y$. $X$ and $Y$,respectively,are

$H_3BO_3$ or $B(OH)_3$ is considered as an acid because its molecule