Graph between  log xm and  log P is a straight line at angle  450 with intercept OA as shown. Hence,  xm at a pressure of 2 atm  is

Applying freudlich adsorption isotherm, xm=kp1/n  Where,  ‘x’ is the mass of the gas adsorbed on a mass  ‘m’ of the adsorbent at a pressure  P.k and  n are constants which depend on the nature of the adsorbent and the gas at a particular temperature.⇒log⁡x/m=log⁡k+1nlog⁡pk=2,1n=1⇒xm=kp∴xm=4