Nitrogen gas is adsorbed on charcoal to the extent of  $0.387c{m}^3/g$ at a pressure of 1.6 atm and at temperature of 200 K, but at 250 K the same amount of adsorption was achieved only when the pressure was increased to 32 atm. The magnitude of molar enthalpy of adsorption (in kcal/mol) of nitrogen on charcoal is_________ 

$(\ln 20=3.0,R=2calmo{l}^{-1}{K}^{-1})$