[ELI5] Why does soap mixed with water create pressure in a closed container?


While cleaning out a Tupperware container with a mixture of soap and water the lid blew off it made me wonder, why is this happening? Is there some sort of chemical reaction taking place that produces gas? I realize bubbles are formed but I thought soap increased the surface tension of the liquid then trapped the already present gas from the mixing action. The lid blowing off my container leads to be believe that maybe some liquid is being converted into a gas to cause a pressure increase.

In: Chemistry

Was it hot water? That could have made the air expand.