Which statement about benzene-iodine-air equilibrium is true?

  • Thread starter Thread starter mister_mister3
  • Start date Start date
  • Tags Tags
    Equilibrium
Join the discussion
Registration is free. Ask a follow-up in this thread, or start your own.
3 replies · 5K views
mister_mister3
Messages
7
Reaction score
0
A simple question, it would seem, but I'm missing something..
This is a question in my text.

Q: Consider a stoppered flask containing benzene, iodine, and air, which has reached equilibrium at 298K. Which one of the following statements concerning the system at equilibrium is true?

a) The pressure of the vapour phase is not constant.
b) Evaporation of the liquid continues.
c) The colour of the liquid phase will change.
d) The mass of the solid iodine is not constant.

A: I haven't yet had my text throw me a curveball, but I have found numerous errors which I've confirmed with administrators of the course I'm taking. This one stumps me, which makes me think there's an error. For this one, they all seem untrue. for a), I would think that the pressue of the vapour phase would stay constant unless there were a change in temp. for b) at equilibrium, would evaporation not cease? c) the colour of the liquid will change - obviously not true, since there would have to be a change in temp, or pressure and for d) the iodine would have reached a point of saturation in the benzene at equilibrium, so that couldn't change either...

Can anyone point out what I'm missing? Any help is greatly appreciated!
 
Chemistry news on Phys.org
Write out the balanced equation
 
mister_mister3 said:
A simple question, it would seem, but I'm missing something..
This is a question in my text.

Q: Consider a stoppered flask containing benzene, iodine, and air, which has reached equilibrium at 298K. Which one of the following statements concerning the system at equilibrium is true?

a) The pressure of the vapour phase is not constant.
b) Evaporation of the liquid continues.
c) The colour of the liquid phase will change.
d) The mass of the solid iodine is not constant.

A: I haven't yet had my text throw me a curveball, but I have found numerous errors which I've confirmed with administrators of the course I'm taking. This one stumps me, which makes me think there's an error. For this one, they all seem untrue. for a), I would think that the pressue of the vapour phase would stay constant unless there were a change in temp. for b) at equilibrium, would evaporation not cease? c) the colour of the liquid will change - obviously not true, since there would have to be a change in temp, or pressure and for d) the iodine would have reached a point of saturation in the benzene at equilibrium, so that couldn't change either...

Can anyone point out what I'm missing? Any help is greatly appreciated!

my guess is that B is the only one that is true. at equilibrium, the liquid will keep evaporating and condensing in the container, and the rates of both will be equal.
 
agreed

Thanks,

after spending more time examining the situation, I came to the same conclusion myself. It just required some more thought I suppose.