The student made observations related to the contents of the Erlenmeyer flask during the titration. Identify an observation that could have led the student to conclude that a chemical change took place during the titration.

Smoke, heat, bubbles, precipitate, gas, and odor changes, and color change.

Explanation:

There needs to be more of a background on this lab. Although if this is the one I believe you are talking about, it should have turned pink. Since the PH is being changed your indicator changed from clear to pink (if you used the same indicator) this is when your PH from both of your substances are equal (or very close).