Answer
$1.3 \times 10^{3} mL$ chlorine solution
Work Step by Step
First, we need to determine the mass of water:
Mass of water = $ 2.0 \times10^{4} gal \times\frac{3.79 L}{1 gal} \times \frac{1000 mL}{1 L} \times\frac{1.0 g}{mL} = 7.58 \times10^{7} g$
Then, we have to calculate the amount of chlorine needed for the disinfection:
Wt of chlorine = $ 7.58 \times10^{7} g \ water \times \frac{1 g \ chlorine}{1 \times 10^{6}g \ water}
= 75.8 g \ chlorine $
Since, chlorine is only 6 percent of the solution, the volume to be added should be:
Vol of chlorine soln = $ 75.8 g \ chlorine \times\frac{100 \% \ soln}{6.0 \% \ chlorine} \times\frac{1 mL}{1.0 g} = 1263.33 mL = 1.3 \times 10^{3} mL \ chlorine \ solution
$
