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Question

Difficulty: EasySublimation, Magnetization, and Centrifugation

A student needs to separate a solid mixture of iodine crystals and sodium chloride. Which separation technique is most appropriate to isolate pure iodine from the mixture?

  1. SublimationAnswer
  2. B
    Fractional distillation
  3. C
    Magnetization
  4. D
    Centrifugation

Answer

Sublimation is the correct separation technique.
Sublimation is the process where a solid changes directly into a gas without passing through a liquid state. Since iodine readily sublimates when heated while sodium chloride does not, heating the mixture drives off iodine gas, which can then be collected as pure solid crystals on a cool surface.

Step-by-Step Solution

1
Identify the physical properties of the components in the mixture.
Iodine is a solid that readily sublimates (transitions directly from solid to gas) upon heating, while sodium chloride has a very high melting point and does not sublimate.
Choosing an effective separation method depends on exploiting a difference in physical properties between components.
2
Select the appropriate technique based on these properties.
Heating the mixture causes iodine to vaporize directly into gas, leaving sodium chloride behind.
Sublimation allows the selective phase transition of iodine.
3
Collect the purified component.
Condensing iodine vapor on a cold surface yields pure iodine crystals.
Deposition isolates pure solid iodine.

Key Concept

Separation of mixtures by sublimation
Estimated Time:45s
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Topics

Sublimation, Magnetization, and Centrifugation