Wet air containing 10 mole percent water vapor is dried by continuously passing it through a column of CaCl\(_2\) pellets. The pellets remove 50 percent of water from wet air entering the column. The mole percent of water vapor in the product stream exiting the column is ____________________ (rounded off to two decimal places).
Show Hint
In drying/absorption problems, dry-gas moles remain unchanged if only the condensable component is removed.
Use a convenient \(100\) mol basis to convert between mole fraction and mole percent quickly.
Correct Answer: 5.2
Solution and Explanation
Exit water \(=10-5=5\) mol; dry air unchanged \(=90\) mol. Step 3: Total exit moles \(=90+5=95\) mol. Mole percent water at exit: \[ \text{mol % }H_2O=\frac{5}{95}\times 100=5.263% \approx \boxed{5.26\ %}. \]
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