CHEMISTRY · Single correct · A Level · Chemistry · Chemical equilibria (Le Chatelier’s principle and Kc) · Chemical equilibria (Le Chatelier’s principle and Kc)
Problem
At 1 atm pressure and 25 °C, a sample of solid iodine is placed in a sealed, evacuated glass tube and allowed to stand. Which outcome is most consistent with the process being reversible under these conditions?
(a) The violet color of the iodine vapor continues to increase until it becomes opaque, while some solid still remains.
(b) The mass of solid iodine and the intensity of the violet vapor color remain constant after some time.
(c) The pressure in the tube quickly rises to 1 atm and then stays fixed at that value.
(d) Tiny iodine crystals slowly plate out on the cooler walls above the solid, gradually depleting the original sample of solid iodine.