Why does iodine, (s), spontaneously sublime at room temperature?
A)The contact of iodine, (s), with the water vapor in the air causes the sublimation process.
B)Iodine, (s), pulls from the air as it self-oxidizes under sublimation to (g).
C)There is an increase in entropy as solid iodine, (s), sublimes into iodine vapor, (g), because in the gaseous phase energy is more readily dispersed.
D)The reaction of (s)subliming to (g)is highly exothermic and therefore proceeds spontaneously.

Question

Why does iodine,  (s), spontaneously sublime at room temperature?
A)The contact of iodine, (s), with the water vapor in the air causes the sublimation process. 
B)Iodine, (s), pulls from the air as it self-oxidizes under sublimation to (g). 
C)There is an increase in entropy as solid iodine, (s), sublimes into iodine vapor, (g), because in the gaseous phase energy is more readily dispersed. 
D)The reaction of (s)subliming to (g)is highly exothermic and therefore proceeds spontaneously.

Quizplus · Accepted Answer

Sublimation of solid iodine to vapor phase increases entropy, which is a thermodynamically favored process. This is because in the gaseous state, the molecules have more degrees of freedom and greater energy dispersal, resulting in an increase in entropy. The sublimation of solid iodine to vapor phase is an endothermic process, not exothermic, so option D can be eliminated. Option A is incorrect because the sublimation of solid iodine is not dependent on the presence of water vapor. Option B is also incorrect because iodine does not undergo self-oxidation during sublimation.

Why Does Iodine, (S), Spontaneously Sublime at Room Temperature