What happens inside an empty tank when it is filled with air?

An Empty Tank Is Slowly Filled With Air. Water Is Then Added To The Tank, Decreasing The Volume For The Air In The Tank. The Temperature Remains Constant

pressure is created at the wall's surface

Explanation:

When air is filled in an empty tank, air molecules try to spread through out the tank. The gas molecules has random and continues motion due to which they possess kinetic energy. Due to this energy air molecules continuously strike with the wall of the tank and apply force on the wall of tank due to which reaction force is applied on air molecule In this way pressure is created on tanker's walls and it becomes hot.