Podcast
Questions and Answers
What color does phenolphthalein turn in a basic solution?
What color does phenolphthalein turn in a basic solution?
Which of the following indicators has a pH range that includes neutral pH?
Which of the following indicators has a pH range that includes neutral pH?
At what pH range does methyl red change color?
At what pH range does methyl red change color?
What is the color of bromothymol blue in an acidic solution?
What is the color of bromothymol blue in an acidic solution?
Signup and view all the answers
Which acid-base indicator shows a color change from red to yellow at a pH below 4?
Which acid-base indicator shows a color change from red to yellow at a pH below 4?
Signup and view all the answers
Study Notes
Acid-Base Indicators Overview
- Acid-base indicators are substances that change color at a specific pH range, useful for determining acidity or alkalinity.
- Each indicator has a unique pKin and pH range where it changes color.
Key Indicators and Their Properties
-
Thymol Blue (Acid):
- pKin: 1.7
- pH range: 1.2-2.8
- Color: Red in acidic solutions.
-
Bromophenol Blue:
- pKin: 4.1
- pH range: 3.0-4.6
- Color: Yellow in acidic solutions.
-
Methyl Orange:
- pKin: 3.7
- pH range: 3.1-4.4
- Color: Red in acidic environments.
-
Methyl Red:
- pKin: 5.0
- pH range: 4.2-6.3
- Color: Red in more acidic conditions.
-
Congo Red:
- No pKin listed.
- pH range: 3.0-5.0
- Color: Blue in acidic solutions.
-
Litmus:
- pKin: 6.5
- pH range: 5.5-7.5
- Color: Red in acidic, Blue in alkaline solutions.
-
Phenol Red:
- pKin: 7.8
- pH range: 6.8-8.4
- Color: Yellow in alkaline conditions.
-
Thymol Blue (Base):
- pKin: 8.9
- pH range: 8.0-9.6
- Color: Yellow in alkaline solutions.
-
Bromothymol Blue:
- pKin: 7.1
- pH range: 6.0-7.6
- Color: Yellow in acidic solutions.
-
Phenolphthalein:
- pKin: 9.7
- pH range: 8.3-10.0
- Color: Colorless in acidic, turns to pink in alkaline solutions.
Color Changes in Different Solutions
- Acidic solutions typically display red colors with indicators like Methyl red, Methyl orange, and Thymol blue (acid).
- Yellow is observed in bromothymol blue and phenol red in acidic solutions.
- Alkaline solutions change color predominantly to yellow or blue, particularly with indicators like Thymol blue (base) and Litmus.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your knowledge on various acid-base indicators, including their pKin values, pH ranges, and color changes. This quiz will help reinforce your understanding of how these indicators function in different pH environments.
