Write reactions to justify amphoteric nature of aluminium.
A substance is called amphoteric if it displays characteristics of both acids and bases. Aluminium dissolves in both acids and bases, showing amphoteric behaviour.
$(i)\,\,2A{l_{(s)}} + 6HC{l_{(aq)}} \to 2A{l^{3 + }}_{(aq)} + 6C{l^ - }_{(aq)} + 3{H_{2(g)}}$
$(ii)\,\,2A{l_{(s)}} + 2NaO{H_{(aq)}} + 6{H_2}{O_{(aq)}} \to 2N{a^ + }{[Al{(OH)_4}]^ - }_{(aq)} + 3{H_{2(g)}}$
When orthoboric acid $({H_3}B{O_3})$ is heated, the residue left is
$BF_3$ on hydrolysis forms
Explain atomic radius of elements of boron family.
The tendency of $BF_3, BCl_3$ and $BBr_3$ to behave as Lewis acid decreases in the sequence
Explain ionization enthalpy and electro-negativity for elements of Boron family.