Final answer:
To calculate the new concentration of NaCl solution after dilution, the final volume of the solution is determined to be 150.0 mL by adding the initial volume and the volume of water added. Using the molarity equation, the new concentration is found to be 0.125 M.
Step-by-step explanation:
To find the new concentration of the NaCl solution after dilution, we use the concept of molarity and the principle of conservation of mass. The amount of solute (NaCl in this case) stays the same, but the volume increases when more solvent (water) is added.
The initial molarity (Mi) of the NaCl solution is 0.150 M and the initial volume (Vi) is 125.0 mL. The volume of water added is 25.0 mL.
The final volume (Vf) is the sum of the initial volume and the volume of water added:
Vf = Vi + volume of water added
Vf = 125.0 mL + 25.0 mL
Vf = 150.0 mL
The new concentration Cf can be calculated using the formula:
Ci × Vi = Cf × Vf
(0.150 M) × (125.0 mL) = Cf × (150.0 mL)
Cf = (0.150 M × 125.0 mL) / 150.0 mL
Cf = 0.125 M
The final volume of the solution is 150.0 mL.