Question: A researcher needs to dilute a 10M solution to a 1M solution. If they take 100 mL of the 10M solution, how much water should they add?

Options:

1. 900 mL
2. 1000 mL
3. 1100 mL
4. 1200 mL

Correct Answer: 900 mL

Solution:

Using the dilution formula C1V1 = C2V2, 10M * 100mL = 1M * V2. V2 = 1000 mL. Water to add = 1000 mL - 100 mL = 900 mL.