Waiting for answer This question has not been answered yet. You can hire a professional tutor to get the answer.

QUESTION

# How would you explain the phase diagram of sulphur?

A phase diagram is a chart that shows the conditions of pressure and temperature at which distinct phases occur and coexist at equilibrium.

The lines on a phase diagram divide into regions – solid, liquid, and gas.

The phase diagram of sulfur is

The diagram is complicated by the fact that sulfur can exist in two crystalline forms: rhombic and monoclinic.

Let's look first at the four areas:

• Pink — only rhombic sulfur
• Brown — only monoclinic sulfur
• Green — only liquid sulfur
• Blue — gaseous sulfur

The corresponding curves are:

• lower left to ① — the sublimation curve of rhombic "S": "S(rhombic)" ⇌ "S(g)"
• ① to② — the sublimation curve of monoclinic "S": "S(monoclinic") ⇌"S(g)"
• ② to upper right — the vapour pressure curve of liquid "S": "S(l)" ⇌ "S(g)"
• ① to ③ — the transition curve for "S(rhombic)" ⇌ "S(monoclinic)"
• ② to ③ — the melting point curve for "S(monoclinic) ⇌ S(l)"
• ③ to top — the melting point curve for "S(rhombic) ⇌ S(l)"

There are three triple points:

• ① ("95.4 °C", 1 × 10^"-4"color(white)(l) "atm") — rhombic "S" is in equilibrium with monoclinic "S", and both have the same vapour pressure.
• ② ("119 °C", 5× 10^-4color(white)(l) "atm") — monoclinic "S" melts; this is the triple point for "S"_"m" ⇌ "S"_"l" ⇌ "S"_"g".
• ③ ("151 °C, 1288 atm") — rhombic, monoclinic, and liquid "S" are at equilibrium.

The critical point — where liquid and gaseous "S" have the same density — is off to the right at "1041 °C and 203.3 atm".