The Langmuir adsorption isotherm is given by the equation: = KP / 1 + KP where is the fractional coverage of the adsorbent surface, K is the Langmuir constant 0.2 L/mol in this case , and P is the pressure 5 atm .First, we need to find the fractional coverage of the adsorbent surface: = 0.2 L/mol * 5 atm / 1 + 0.2 L/mol * 5 atm = 1 / 1 + 1/5 = 1 / 6/5 = 5/6The maximum adsorption capacity of the adsorbent material is the product of the fractional coverage and the total number of adsorption sites available on the material N . However, the problem does not provide information about the total number of adsorption sites N . Therefore, we can only determine the fractional coverage of the adsorbent surface, which is 5/6 or approximately 0.8333.