Question

Answer this based on the the P-T phase diagram of CO₂: What happens when CO₂ at 4 atm pressure is cooled from room temperature at constant pressure?

Answer 1

Please refer to attachment for the P-T phase diagram of CO2

CO2 at 4 atm and at room temperature  say 25 °c is a vapour.

Now if the pressure is 4 atm which is less than 5.11atm .

Hence the CO2 will condense directly into solid without becoming liquid.

Reason :

 The temperature lies between -60°C which is in solid phase.