Question

At temperatures and pressures above the critical point, carbon dioxide behaves as a:

• A. Semiconductor
• B. Supercritical $C{O}_2$
• C. $CO$
• D. Dry ice

Answer 1

Answer: (B)

Supercritical $C{O}_2$

Supercritical carbon dioxide is a fluid state of carbon dioxide where it is held at or above its critical temperature and critical pressure. Carbon dioxide usually behaves as a gas in air at standard temperature and pressure (STP), or as a solid called dry ice when frozen. If the temperature and pressure are both increased from STP to be at or above the critical point for carbon dioxide, it can adopt properties midway between a gas and a liquid.