Answer:
1000 mL.
Step-by-step explanation:
From the question given above, the following data were obtained:
Volume of stock solution (V1) = 40 mL
Molarity of stock solution (M1) = 1.25 M
Molarity of diluted solution (M2) = 0.05 M
Volume of diluted solution (V2) =...?
The volume of diluted solution can be obtained as shown below:
M1V1 = M1V1
1.25 × 40 = 0.05 × V2
50 = 0.05 × V2
Divide both side by 0.05
V2 = 50/0.05
V2 = 1000 mL
Therefore, the stock solution must be diluted to 1000 mL to obtain a 0.05 M solution of NaCl.