pH indicators are:

pH indicators are:

• A. Chemicals that change colour depending on the pH of the solution they are placed in
• B. Substances that measure temperature
• C. Gases that indicate pH by smell
• D. Compounds that neutralize bases

Answer: (A)

pH indicators reveal how acidic or basic a solution is by changing color as the hydrogen ion concentration changes. These indicators are chemicals whose molecular structure shifts with protonation and deprotonation, so in an acidic environment they display one color, and in a basic environment they show a different color. Because each indicator changes color over a specific pH range, choosing the right one lets you read the pH more accurately for the situation. For instance, litmus dye turns red in acidic solutions and blue in basic ones; phenolphthalein is colorless in acid and pink in base; bromothymol blue shifts from yellow to blue as pH increases. A universal indicator can show a full spectrum of colors across the pH scale. They aren’t temperature meters, they aren’t gases detected by smell, and they don’t neutralize bases. They simply indicate pH through color change.

pH indicators reveal how acidic or basic a solution is by changing color as the hydrogen ion concentration changes. These indicators are chemicals whose molecular structure shifts with protonation and deprotonation, so in an acidic environment they display one color, and in a basic environment they show a different color. Because each indicator changes color over a specific pH range, choosing the right one lets you read the pH more accurately for the situation. For instance, litmus dye turns red in acidic solutions and blue in basic ones; phenolphthalein is colorless in acid and pink in base; bromothymol blue shifts from yellow to blue as pH increases. A universal indicator can show a full spectrum of colors across the pH scale. They aren’t temperature meters, they aren’t gases detected by smell, and they don’t neutralize bases. They simply indicate pH through color change.