How can a chlorine leak be detected?

Chlorine leaks can be effectively detected using ammonia solution vapors because chlorine and ammonia can react to produce visible indicators, such as a white cloud of ammonium chloride. When ammonia vapors come into contact with chlorine gas, this reaction becomes apparent, which can alert personnel to the presence of a chlorine leak.

The other methods listed are less effective for chlorine leak detection. A color change test may not reliably indicate the presence of chlorine specifically, as it depends on specific reagents and conditions that may not be readily applicable in all environments. Observing evaporated water does not provide clear evidence of a chlorine leak, since evaporation can occur for many reasons unrelated to chlorine presence. Measuring temperature changes is similarly not a direct method for detecting chlorine gas since temperature fluctuations can occur due to various environmental factors.