Final answer:
The concentration of the diluted NaCl solution is 10.5 M.
Step-by-step explanation:
To determine the concentration of the diluted solution, we can use the equation:
C1V1 = C2V2
Where C1 is the initial concentration, V1 is the initial volume, C2 is the final concentration, and V2 is the final volume.
In this case, we have:
C1 = 3 M (from the 700 mL of 3-M NaCl solution)
V1 = 700 mL
C2 = ? (what we want to find)
V2 = 200 mL (the amount of water added)
Plugging these values into the equation, we have:
3 M * 700 mL = C2 * 200 mL
C2 = (3 M * 700 mL) / 200 mL
C2 = 10.5 M
So, the concentration of the diluted NaCl solution is 10.5 M.