A hazardous chemical is leaking from a tank truck. Rescue workers need to evacuate people who live near the accident. Why are more people likely to be affected if the chemical is a gas, rather than a liquid?
gases travel faster than liquids
basically it all comes down to molecules and the structure of elements gases are held together by weaker forces thus only require minimal excitation to transmit but liquids have stronger bonds , with this in mind we clearly see why it is more prudent to rescue those affected by the gas sooner.