Answer: 4) Concentrate it
Explanation:
Answer:- 544.5 mL of water need to be added.
Solution:- It is a dilution problem. The equation used for solving this type of problems is:

where,
is initial molarity and
is the molarity after dilution. Similarly,
is the volume before dilution and
is the volume after dilution.
Let's plug in the values in the equation:



Volume of water added = 907.5mL - 363mL = 544.5 mL
So, 544.5 mL of water are need to be added to the original solution for dilution.
Answer is: carbon dioxide (CO₂) can affect the end point of the titration.
Carbon dioxide, or carbon(IV) oxide, reacts with water and form carbonic acid, which can affect the end point of the titration, because more base is needed for neutralization of partially neutralized stomach acid.
Balanced chemical reaction of carbon dioxide and water: CO₂ + H₂O → H₂CO₃.