Which of the following is FALSE with regard to liquid oxygen?

Which of the following is FALSE with regard to liquid oxygen?

• A. It is stored at -183 degrees C in special cryogenic containers
• B. It is maintained at 18 psi
• C. As tanks slowly warm, the oxygen evaporates
• D. Touching the fill valve can result in burns

Answer: (B)

Liquid oxygen is stored in cryogenic dewars at its boiling point, about -183°C. At that temperature its vapor pressure is essentially atmospheric, so the system is designed to vent excess gas to keep pressure near ambient rather than holding a fixed higher pressure. If the tank warms, LOX boils more rapidly and produces more gas, which is vented to prevent over-pressurization. The claim that it is maintained at 18 psi is not correct because there isn’t a constant 18-psi target inside a typical LOX storage dewar; pressure is governed by temperature and vapor pressure, with venting balancing any rise. The other statements are true: LOX is kept extremely cold in special containers, it slowly boils off as it warms, and touching the fill valve can cause severe cryogenic burns due to the extreme cold.

Liquid oxygen is stored in cryogenic dewars at its boiling point, about -183°C. At that temperature its vapor pressure is essentially atmospheric, so the system is designed to vent excess gas to keep pressure near ambient rather than holding a fixed higher pressure. If the tank warms, LOX boils more rapidly and produces more gas, which is vented to prevent over-pressurization. The claim that it is maintained at 18 psi is not correct because there isn’t a constant 18-psi target inside a typical LOX storage dewar; pressure is governed by temperature and vapor pressure, with venting balancing any rise. The other statements are true: LOX is kept extremely cold in special containers, it slowly boils off as it warms, and touching the fill valve can cause severe cryogenic burns due to the extreme cold.