Kinetic Interpretation Of Pressure

The kinetic interpretation of pressure, developed in NCERT Class 11, Chapter 13 (Kinetic Theory), treats a gas as a large number of tiny molecules in ceaseless random motion, and pressure emerges from their collisions with the container walls. Each molecule that strikes a wall and rebounds undergoes a change in momentum, and by Newton's second law this rate of momentum change is a force; averaged over the wall area it gives the pressure. This leads to the expression $P=\frac{1}{3}\frac{mN}{V}\overline{v^2}$, showing pressure depends on molecular mass, number density and mean square speed. The option about gravitational attraction is wrong because intermolecular gravity is utterly negligible for gas molecules. The option about electrostatic repulsion is wrong since ideal gas molecules and walls are treated as neutral. The option about chemical bonding is wrong because bonding would trap molecules rather than let them rebound elastically. As a consistency check, the mechanism correctly predicts that heavier or faster molecules exert more pressure, matching everyday observations of hot, dense gases pressing harder on their containers.