A gas that follows Boyle’s law, Charles’ law and Avogadro law strictly is called an ideal gas. Such a gas is hypothetical.

It is assumed that inter molecular forces are not present between the molecules of an ideal gas.

Real gases follow these laws only under certain specific conditions when forces of interaction are practically negligible. In all other situations these deviate from ideal behaviour.

The three laws, Boyle’s law, Charles’ law and Avogadro law can be combined together in a single equation which is known as ideal the gas equation.pV = n RT is known as ideal gas equation.

The value of R depends upon the units in which p, V and T are measured.

The ideal gas equation is a relation between four variables and it describes the state of any gas, Therefore, it is also called the equation of state.