Final answer:
A simple test for chlorine gas involves exposing damp litmus paper to the gas, where it will bleach and turn white if chlorine is present.
Step-by-step explanation:
A simple laboratory test for chlorine gas is to expose it to damp litmus paper. Chlorine gas is a powerful oxidizing agent and bleaches the dye in the litmus paper, causing it to turn white.
This is a distinctive test for chlorine because other gases do not have this bleaching effect. If chlorine gas is present, the litmus paper will quickly lose its color and turn white. It is important to note that the test should be conducted in a fume hood to avoid inhalation of chlorine which is hazardous.