Wet air containing 4.0mole% water vapor is passed through a column of calcium chloride pellets. The pellets adsorb 97.0% of the water and none of the other constituents of the air. The column packing was initially dry and had a mass of 3.40kg, following 5.0 hours of operation the pellets are reweighed and found to have a mass of 3.54 kg.

(a) Calculate the molar flow rate (mol/h) of the feed gas and the mole fraction of water vapor in the product gas.

(b) The mole fraction of water in the product gas is monitored and found to have the value calculated in part (a) for the first 10 hours of operation, but then it begins to increase. What is the most likely cause of the increase? If the process continues to run, what will the mole fraction of water in the product gas eventually be?