Titration is best described as a method used to determine the composition of a sample by incrementally adding a standard solution until what occurs?

• A. a color change, a precipitate, or a pH change
• B. the solution boils
• C. the solution freezes
• D. the solution becomes a gas

Answer: (A)

Titration relies on detecting the moment the chemical reaction between the sample and the standard solution is complete. That end point is shown by signals you can observe, such as a color change from an indicator, the formation or disappearance of a precipitate, or a noticeable shift in pH. These signals indicate the reaction has reached its end, allowing you to calculate the sample’s concentration. Boiling, freezing, or evolving a gas are unrelated to signaling the completion of the titration, so they don’t describe how titration works.