Question

A certain substance, X, has a triple-point temperature of 20°C at a pressure of 2.0 atm. Which one of the statements cannot possibly be true?

A. X can exist as a liquid above 20°C.
B. X can exist as a solid above 20°C.
C. Liquid X can exist as a stable phase at 25°C, 1 atm.
D. Both liquid and solid X have the same vapor pressure at 20°C.
E. All of the above are true.

Answer 1

Answer:

Option B is incorrect.

Explanation:

Observe the graph that has been attached along with the answer, that is the general representation of a substance approaching and during triple point phase.

Now, checking the options one by one

A. We verify that a substance can be in liquid form above its triple point, which in this case is 20°C. So this is a true statement.

B.This is a false statement because all the solid state is exhibited before the triple point temperature ie. 20°C. So, false.

C. By stable phase, we mean that a substance exhibits only one state. On increasing the temperature and lowering the pressure, we see the only state possible is the vapor phase. So this statement has to be true.

D. This is a true statement and it is a fact.

E. All the statements are not true so this is not the correct option.

Therefore, only option B is an incorrect option.

Answer 2

Answer:

Answer C is not true.

Explanation:

Answer C is false because the liquid state can only exist past 2 atm and in this answer, it is 1 atm.