Here are the essential concepts you must grasp in order to answer the question correctly.
pH Indicators
pH indicators are substances that change color in response to changes in pH levels. They are used to determine the acidity or basicity of a solution. Different indicators have specific pH ranges over which they change color, making them suitable for various applications in titrations and pH testing.
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Acid-Base Chemistry
Acid-base chemistry involves the study of acids, bases, and their reactions. Acids donate protons (H+) in solution, while bases accept protons. The pH scale, ranging from 0 to 14, quantifies the acidity or basicity of a solution, with values below 7 indicating acidity and above 7 indicating basicity.
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Arrhenius Acids and Bases
Color Change of Indicators
The color change of pH indicators occurs due to structural changes in the indicator molecules when they gain or lose protons. For example, phenolphthalein is colorless in acidic solutions and turns pink in basic solutions, while bromthymol blue is yellow in acidic conditions and blue in basic conditions. Understanding these transitions helps in selecting appropriate indicators for specific pH ranges.
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