Question

Which of the following halogens can be purified with sublimation?
A. \[{F_2}\]
B. \[C{l_2}\]
C. \[B{r_2}\]
D. \[{I_2}\]

Answer 1

Hint: Sublimation is the conversion of substance from solid phase directly to gaseous phase, there is no intermediate phase. Now, by using this you can easily find the correct option from the given ones.

Complete step by step answer:
It is known to you that sublimation is caused by the absorption of heat which provides enough energy for some molecules to overcome the attractive forces of their neighbours and escape into the vapour phase.

Now, coming to the question we can easily find the correct option by inspecting each of the given option:
Option A: Fluorine (\[{F_2}\]) is a pale yellow diatomic gas and it has the highest electronegativity. Since, it is a gas so sublimation method cannot be used for its purification.
Option B: Chlorine (\[C{l_2}\]) is a greenish yellow colored diatomic gas and it has the highest electron affinity. Since, it is a gas so sublimation cannot be used for its purification.
Option C: Bromine (\[B{r_2}\]) is a reddish brown liquid at room temperature. Since, it is a liquid so sublimation method cannot be used for its purification.
Option D: Iodine (\[{I_2}\]) is a dark purple-black colored solid at room temperature. Since it is a solid and on heating it directly gets converted into vapor so sublimation method can be used for its purification.

Therefore, from above we can easily conclude that option D is the correct option.

Note: a) It should be remembered to you that iodine is commonly used as a topical disinfectant in the form of betadine or tincture of iodine.
b) Also, Iodine is used to prevent iodine deficiency and its consequences including goiter.