Pressure versus volume graph for a real gas and an ideal gas are shown in the figure. Answer the following questions on the basis of this graph:
$(i)$ Interpret the behaviour of real gas with respect to ideal gas at low pressure.
$(ii)$ Interpret the behaviour of real gas with respect to ideal gas at high pressure.
$(iii)$ Mark the pressure and volume by drawing a line at the point where real gas behaves as an ideal gas.

(N/A) $(i)$ The real gas shows very small deviation from ideal behaviour at low pressure because the two curves almost coincide at low pressure.
$(ii)$ The real gas shows large deviations from ideal behaviour at high pressure as the curves are far apart.
$(iii)$ At the point where both the curves intersect each other,the real gas behaves as an ideal gas. At this specific pressure and volume,the compressibility factor $Z$ is equal to $1$.