Chapter SM, Problem 1PQ

Interpretation Introduction

Interpretation:

The transition that represents condensation of gas to liquid has to be determined.

Concept Introduction:

A phase diagram is a representation or chart that shows thermodynamic conditions of the substances at various temperatures and pressures. It consists of lines that represent equilibrium or phase boundaries. These lines are indication of transition of substance from one phase to another. The triple point is point on phase diagram where all three phases of matter coexist together.

Answer to Problem 1PQ

Option (B) is the correct one.

Explanation of Solution

Reason for correct option:

In given phase diagram, A represents solid phase of substance. B denotes liquid phase, D indicates vapor phase. C indicates triple point at which solid, liquid and vapor phases of substance exist in equilibrium with each other. Since D is point that corresponds to gas and B represents point where substance exists in its liquid phase, condensation of gas to liquid is shown by transition from D to B.

Reason for incorrect option:

Transition from B to A represents conversion of substance from liquid to solid phase. So freezing is done. Hence option (A) is incorrect.

D represents vapor phase of substance that is final state of substance in transition from C to D. But condensation involves cooling of gas to liquid. Hence option (C) is incorrect.

Transition from A to D represents conversion of substance from solid to vapor phase. So sublimation is done. Hence option (D) is incorrect.

Conclusion

The transition from D to B represents condensation of gas to liquid. Hence, option is (B) is correct.