Question

The phase diagram for sulfur is shown above. Which statement about this diagram is correct?

(A) The critical point is above 154 °C and 103 atm.

(B) There is only one triple point in the diagram.

(C) Monoclinic sulfur is more dense than rhombic sulfur at any temperature.

(D) Monoclinic sulfur forms rhombic sulfur at higher pressures or lower temperatures

Answer 1

with the help of the phase diagram courtesy google image , it seems to be option d.

The reason being at lower temperatures or higher pressures, crystalline reformation takes place.

By looking at the phase diagram of sulphur containing of different crystalline structures there are two things to be noted.

(i) At lower temperatures and constant pressures, sulphur's crystalline structure changes from Monoclinic to Rhombic.

(ii) At higher pressure and constant temperatures, Sulphur's crystalline structure changes to Rhombic.