Answer:
<u>Heating water with an open flame</u>
<u>Explanation:</u>
Remember, we are told in the label that Acetone is a "flammable liquid and vapor." <em>Being flammable means the substance can easily be set on fire</em>, and we would expect an open flame from heating water to trigger an explosion (a disaster) in which the Acetone is set on fire causing life-threatening dangers to the second group of students.
