Which of the following is the test for chlorine gas? a. damp blue litmus is placed in the gas b. a lit wooden splint is placed in the gas c. a glowing wooden splint is placed in the gas d. the gas is bubbled in limewater

Alidded glass container is filled with a colored gas. after a period of time, it is observed that the gas is uniformly spread throughout the box and that the movement has slowed considerably. next, a warm iron plate is carefully placed under the box. why is there resumed movement of the gas in the container?