Question

assuming 50 tons of pressure, at which temperatures is benzene a solid, liquid, or gas?
it is a solid at 7 degrees, a liquid at 10 and 16 degrees, and a gas at 32 degrees celsius.
it is a solid at 0 degrees, a liquid at 5 and 7 degrees, and a gas above 10 degrees celsius.
it is a liquid at 5, 7 and 10 degrees, and a gas above 20 degrees celsius.
it is a solid at 5 degrees, a liquid at 7 and 10 degrees, and a gas at 16 degrees celsius.

Explanation:

Step1: Locate 50 tons on the pressure - axis

Locate the 50 - tons mark on the vertical pressure - axis of the phase diagram.

Step2: Analyze temperature - phase relationships

For temperatures below approximately 6 degrees Celsius, benzene is in the solid phase. Between about 6 and 12 degrees Celsius, it is in the liquid phase. Above about 12 degrees Celsius, it is in the gas (vapor) phase.

Step3: Evaluate each option

• Option 1: 7 degrees (liquid), 10 and 16 degrees (liquid and gas respectively), 32 degrees (gas) - Correct as 7 degrees is liquid, 10 degrees is liquid and 32 degrees is gas.
• Option 2: 0 degrees (solid), 5 and 7 degrees (solid and liquid respectively), above 10 degrees (gas) - Incorrect as 5 degrees is solid not liquid as stated.
• Option 3: 5, 7 and 10 degrees (5 degrees is solid not liquid as stated) - Incorrect.
• Option 4: 5 degrees (solid), 7 and 10 degrees (liquid), 16 degrees (gas) - Correct.

Answer:

A. It is a solid at 7 degrees, a liquid at 10 and 16 degrees, and a gas at 32 degrees celsius.
D. It is a solid at 5 degrees, a liquid at 7 and 10 degrees, and a gas at 16 degrees celsius.