Question

How do you get high pressure CO₂ into a sealed glass tube?

Answer 1

Take solid carbon dioxide (known as dry ice) in to a glass tube of thick wall and one side closed. After filling the glass tube upto half of its volume with CO₂ solid, seal the open mouth of the glass tube by using a flame carefully. Cool the sealed to tube to room temperature and to get CO₂ in the sealed tube. Due to high pressure in the sealed tube CO₂ gas becomes liquified.

CO2 exists as gas at STP and can be frozen to -78 °C to get solid CO2. When it is sealed in a tube and allowed its temperature and pressure above its critical temperature 31.1 °C and critical pressure 72.9 atm , then it forms a supercritical CO₂ liquid. CO₂ liquid in sealed tube is a low cost, chemically stable, non-toxic, readily available, and non-flammable industrial solvent for exacting a wide range of compounds.