Which of the following gas analyzers requires an electrode to be heated to 700° C?

Explanation:

The catalytic combustion detector is the gas analyzer that requires an electrode to be heated to 700° C. This type of detector works by oxidizing the gas sample over a heated catalyst, causing a temperature change due to the heat of combustion. The temperature change is then measured and related to the concentration of gas.

This process is different from other types of gas analyzers listed:

• Infrared gas analyzer: Measures gas concentrations based on the absorption of infrared radiation.
• Flame ionization detector: Uses a hydrogen flame to ionize organic compounds.
• Thermal conductivity detector: Operates based on thermal conductivity differences between the sample and a reference gas.