Initial volume is 8.5. Could I get best answer??
B. A solar cycle usually lasts 11 years.
Answer: I think the answer is 2.5 M.
Explanation: Formula: M = n/v
M= 10 mol / 4L
M= 2.5 M
The accepted concentration of chlorine is 1.00 ppm that is 1 gram of chlorine per million of water.
The volume of water is
.
Since, 1 gal= 3785.41 mL
Thus, 
Density of water is 1 g/mL thus, mass of water will be
.
Since, 1 grams of chlorine →
grams of water.
1 g of water →
g of chlorine and,
of water →86.6 g of chlorine
Since, the solution is 9% chlorine by mass, the volume of solution will be:

Thus, volume of chlorine solution is 9.62\times 10^{2} mL.