ANS:A - become hotter.

A gas having a negative Joule-Thompson coefficient will not become hotter when throttled; it will become cooler. The Joule-Thompson coefficient (μ) indicates how the temperature of a gas changes when it undergoes throttling or expansion without any external heat exchange. A negative Joule-Thompson coefficient means that the gas will cool down when it expands, while a positive coefficient means that the gas will heat up. When a gas with a negative Joule-Thompson coefficient is throttled, it expands rapidly, leading to a decrease in pressure. According to the Joule-Thompson effect, this expansion causes a decrease in temperature. As a result, the gas becomes cooler. So, to clarify, when a gas with a negative Joule-Thompson coefficient is throttled, it will become cooler, not hotter.