Question

andrea is performing an experiment in which she needs to know when a strong acid is present. she is not sure which indicator to use, so she looks up the following table in her science textbook. according to the textbook, which indicator should andrea use? hint: neutral substances have a ph of 7. acids have a ph that is less than 7, and bases have a ph that is greater than 7. a. phenolphthalein b. phenol red c. trinitrobenzoic acid d. thymol blue

Explanation:

Step1: Recall acid - pH relationship

Acids have pH < 7. Strong acids have lower pH values.

Step2: Analyze indicator pH ranges

Thymol Blue has a pH range of 1.2 - 2.8 which is within the acidic range and suitable for detecting strong acids. Phenol Red (6.4 - 8.0) is more for slightly acidic to slightly basic. Phenolphthalein (8.0 - 10.0) and trinitrobenzoic acid (12.0 - 13.4) are for basic substances.

Answer:

D. thymol Blue