Question

Iodine is often seen as an example of a substance that changes directly from a solid to a gas. However,
data books that give the standard physical
measurements for substances show values for the
melting point (114°C) and boiling point (184°C) of
iodine at atmospheric pressure.

Explain why iodine seems to miss out the
liquid stage if crystals are heated strongly in a
boiling tube.
​

Answer 1

(i) When Iodine crystals are heated, the van der Waals forces are easily overcome and the molecule breaks into the gas phase. They sublime and form a purple colored dense vapor.

(ii) When Iron nail (Ferrum) is dipped in Copper sulphate (CuSO

4

) there takes reaction between them and copper sulphate changes its color from blue to light green. This shows Iron is more reactive than Copper, it can replace Copper from CuSO

4

.

hope it helps you ✌️✅✅✅

Answer 2

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