An ideal gas is defined as one in which all collisions between atoms or molecules are perfectly eleastic and in which there are no intermolecular attractive forces. A gas is said to be an ideal gas if it has the following properties: * There is no intermolecular forces between the gas molecules, i.e., gas molecules don't exert any kind of force on each other. * Size of the gas molecules is negligible as compared to the volume occupied by the gas(container's volume).