Chapter 5, Problem 5.58P

You have purchased a gas cylinder that is supposed to contain 5.0 mole% ${\text{Cl}}_{\text{2}}\left(\text{±0}\text{.1\%}\right)$and 95% air. The experiments you have been running are not giving reasonable results, and you suspect that the chlorine concentration in the gas cylinder is incorrect.

To check this hypothesis, you bubble gas from the suspicious cylinder through 2.0 L of an aqueous NaOH solution (12.0 wt% NaOH, SG = 1.13) for exactly one hour. The inlet gas is metered at a gauge pressure of 510 mm H₂O and a temperature of 23°C. Prior to entering the vessel, the gas passes through a flowmeter that indicates a how rate of 2.00 L/mm. At the conclusion of the experiment, a sample of the residual NaOH solution is analyzed and the results show that the NaOH content has been reduced by 23%. What is the concentration of Cl₂in the cylinder gas? (Assume the Cl₂is completely consumed in the reaction ${\text{Cl}}_{\text{2}}+2\text{NaOH}\to {\text{NaOCl+H}}_{\text{2}}\text{O}$.)