Which gas is NOT measured by the gas analyzer?

The gas analyzer typically functions to detect and quantify specific gases that are common in various environments, particularly in industrial and safety contexts. Nitrous oxide, while a significant gas in certain applications such as anesthesiology and as a rocket propellant, is not standardly measured in many basic gas analyses. Instead, gas analysts more commonly focus on gases like carbon monoxide and hydrogen sulfide due to their implications for safety and health in a wide range of scenarios, such as monitoring for toxic or harmful emissions.

On the other hand, explosive limits are measures that indicate the concentration range in which a gas can create an explosion if ignited, which may be included in broader assessments involving flammable gases. Thus, the reason why nitrous oxide is the answer is that it typically does not fall within the focus of standard gas analyzers which prioritize toxic, hazardous, and flammable gases that directly affect safety.