Dewar containers are used to store liquids at extremely low temperatures. What category do these liquids belong to?

Dewar containers are used to store liquids at extremely low temperatures. What category do these liquids belong to?

• A. High-pressure gases
• B. Cryogenic liquids
• C. Solid hazards
• D. Corrosive liquids

Answer: (B)

Liquids kept in Dewar containers fall into the cryogenic liquids category. The defining feature here is the extremely low temperature at which these liquids are stored—often below about -150°C—so they remain liquid despite being cooled to such depths. Dewars are specially designed insulated flasks that minimize heat input, slowing vaporization and keeping the liquid state for longer. Examples include liquid nitrogen and liquid helium. This category is about temperature, not pressure, and not about the material being solid or corrosive. While cryogenic liquids can pose hazards from extreme cold and rapid gas expansion if warmed, the key point is the very low storage temperature that characterizes cryogenic storage.

Liquids kept in Dewar containers fall into the cryogenic liquids category. The defining feature here is the extremely low temperature at which these liquids are stored—often below about -150°C—so they remain liquid despite being cooled to such depths. Dewars are specially designed insulated flasks that minimize heat input, slowing vaporization and keeping the liquid state for longer. Examples include liquid nitrogen and liquid helium. This category is about temperature, not pressure, and not about the material being solid or corrosive. While cryogenic liquids can pose hazards from extreme cold and rapid gas expansion if warmed, the key point is the very low storage temperature that characterizes cryogenic storage.