a) Explain the relation between the surface area of an adsorbent and adsorption amount. [10 Marks] b) In a counter current adsorption process pure gold is going to be separated from a Gold alloy. The gold alloy enters the separator while the content of the gold, calcium, silver, fluorine are 0.6,0.3,0.05 and 0.05Kg/Kg respectively. The alloy concentration after the separation process is 0.2,0.4,0.3 and 0.1Kg/Kg. The adsorption process follow the Freundlich isotherm of Y=1.21.6 i. Calculate the extraction percentage [5 Marks] ii. Calculate the concentration of Gold in the first stage. [15 Marks]