For calibration gas mention, which gas is listed as a calibration gas?

• A. Pentane
• B. Argon
• C. Nitrogen
• D. Helium

Answer: (A)

Calibrating a gas detector means using a gas with a known concentration to set or verify the instrument’s response. For detectors that measure hydrocarbons or volatile organic compounds, a hydrocarbon calibration gas is used so the sensor shows an accurate signal when exposed to similar vapors. Pentane fits this role because it’s a simple hydrocarbon with a well-defined concentration in a calibration mix, providing a reliable, repeatable reference for adjusting the detector’s readings. Inert gases like argon, nitrogen, and helium don’t produce a hydrocarbon signal, so they aren’t used to calibrate hydrocarbon sensors (though they may be used for purging or zeroing in some setups). That’s why pentane is listed as the calibration gas.