One phosphorus, three chlorine, one oxygen

What happens when an acid dissolves?

Why does a plastic bottle that is sealed at a high altitude change it’s shape when taken to lower altitude

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?