Bromothymol blue is an acid-base indicator that changes color over a certain pH range. At approximately which pH value would bromothymol blue appear blue?

• A. $6$
• B. $8$
• C. $11$
• D. $2$

Answer: (B)

Verified step by step guidance

1. Understand that bromothymol blue is an acid-base indicator that changes color depending on the pH of the solution it is in.
2. Recall that indicators have a specific pH range over which they change color, typically centered around their pKa value.
3. Know that bromothymol blue changes from yellow in acidic conditions to blue in basic conditions, with a transition range approximately between pH 6.0 and pH 7.6.
4. Recognize that at pH values below the transition range, bromothymol blue appears yellow, and at pH values above the transition range, it appears blue.
5. Therefore, bromothymol blue would appear blue at pH values higher than its transition range, which is around pH 8.