Write note on aluminothermic process.

Explain the following:

Boron has high melting and boiling point.

Explain the following:

Boron does not form ${\mathrm{B}}^{3+}$ ion.

Explain the following:

${\mathrm{AlCl}}_3$ forms a dimer but ${\mathrm{BCl}}_3$ does not form dimer.

Explain the following:

Boron and aluminium halides behave as Lewis acids.

Explain the following:

Aluminium is stable in air and water.

Explain the following:

No visible reaction occurs when aluminium is left in contact concentrated nitric acid.

Explain the following:

Aluminium containers can be used to store concentrated ${\mathrm{HNO}}_3$.