A black cylinder contains which gas?

A black cylinder contains which gas?

• A. Nitrogen
• B. Oxygen
• C. Nitrous oxide
• D. Helium

Answer: (A)

Gas cylinder color coding is used to identify contents at a glance. In many standard systems, a black-bodied cylinder denotes nitrogen. Nitrogen is an inert gas, not used as a medical gaseous agent for anesthesia, so recognizing the black color helps distinguish it from other gases. Oxygen is typically green, nitrous oxide blue, and other gases have their own distinct colors, so they wouldn’t be black. Keep in mind that color schemes can vary by country and over time, so always verify with the cylinder’s labeling and markings.

Gas cylinder color coding is used to identify contents at a glance. In many standard systems, a black-bodied cylinder denotes nitrogen. Nitrogen is an inert gas, not used as a medical gaseous agent for anesthesia, so recognizing the black color helps distinguish it from other gases. Oxygen is typically green, nitrous oxide blue, and other gases have their own distinct colors, so they wouldn’t be black. Keep in mind that color schemes can vary by country and over time, so always verify with the cylinder’s labeling and markings.