Suggest reasons why the B–F bond lengths in BF₃ (130 pm) and BG₄^– (143 pm) differ.

Explain the difference in properties of diamond and graphite on the basis of their structures.

Rationalise the given statements and give chemical reactions:

• Lead(II) chloride reacts with Cl₂ to give PbCl₄.

• Lead(IV) chloride is highly unstable towards heat.

• Lead is known not to form an iodide, PbI₄.

If B–Cl bond has a dipole moment, explain why BCl₃ molecule has zero dipole moment.

Aluminium trifluoride is insoluble in anhydrous HF but dissolves on addition of NaF. Aluminium trifluoride precipitates out of the resulting solution when gaseous BF₃ is bubbled through. Give reasons.