Activity A (continued from previous page) 4. Explore: Click Reset and change the indicator to Bromthymol blue. Add exactly 8.8 mL of HNO3 to the flask. A. What does the color of the indicator tell you about the current pH of the flask? B. Add one more drop of HNO3. What does the color tell you about the pH now? ¬¬¬¬¬¬¬ C. If you combine the results of this question with the results from question 3B, what do you know about the total pH change caused by adding the last 0.1 mL of HNO3? 5. Apply: Water has a pH of 7. If 0.1 mL (about one drop) of 1.0 M HNO3 is added to 100 mL of water, the result is a solution with a concentration of 0.001 M HNO3. A. What is the pH of 0.001 M HNO3? B. How much did one drop of HNO3 cause the pH of water to change? C. How does this relate to what you determined in question 4C?