Question

How would you obtain a sample of pure iodine from impure iodine?

Answer 1

Hint: For the purification of the impure iodine, you can use the process of sublimation. The impurities present in iodine do not undergo sublimation. Actually here the comparison is based on a chemical test where we have to observe what we are getting after the test.

Complete Step by step answer: As we know that iodine is a nonmetal with only one valence electron present. Although it is a little bit less reactive towards chemical tests and reaction but we can perform certain reactions with this to have the required comparisons and products.
We could obtain a sample of pure iodine from impure iodine through sublimation. Place impure iodine in a china dish. Put the china dish over a low flame. You will observe that violet fumes of iodine are formed. When the formation of the violet fumes of iodine just starts, you keep an inverted funnel on the china dish. Make sure that the inverted funnel is cold. This is because, when the violet fumes of iodine come in contact with the cold surface of the inverted funnel, the violet fumes of iodine will condense.

As a result of this condensation process, tiny crystals of pure iodine will be formed on the cooler sides of the funnel. You can then remove the funnel, use a spatula and collect these tiny crystals of pure iodine in a petri dish or a suitable container.


Note: Sublimation is a process, in which when a solid is heated, it directly forms vapours. Thus, the solid directly enters gaseous state without entering liquid state. When the vapours of sublimed solid are condensed by cooling, they change the state from gaseous to solid without entering the liquid state.