Long Answer TypeAluminium trifluoride is insoluble in anhydrous HF but dissolves on the addition of NaF. Aluminium trifluoride precipitates out of the resulting solution when gaseous BF3 is bubbled through. Give reasons.
Boron exhibits anomalous behaviour in the company of other members of group 13. Explain.
Discuss the diagonal relationship of boron with silicon.
The diagonal relationship is due to the fact that both these elements have almost similar values of atomic radii. electronegativity and ionisation energies. Some important points of similarities are:
(i) Both boron and silicon exhibit typical properties of non-metals i.e. possess high melting and boiling points and are non-conductors of electricity.
(ii) Both elements are semiconductors.
(iii) Both exist in amorphous and crystalline forms.
(iv) Both boron and silicon do not form cations.
(v) Both form weak acids as H3BO3 and H4SiO4.
(vi) Chlorides of both elements get hydrolysed easily.
(vii) Both form metallic compounds known as borides and silicides as:
Short Answer TypeIn some of the reactions, thallium resembles aluminium whereas in others it resembles with group 1 metals. Support this statement by giving some evidences.
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