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pH Scale & Indicator Colors
AP Chemistry · Unit 8 Acids & Bases
Learning Objectives
Relate pH to [H⁺] and [OH⁻]
Identify indicator color at specific pH values
Choose appropriate indicator for a titration
Calculate pOH from pH (pH + pOH = 14)
Key Equations
pH = −log[H⁺]
pOH = −log[OH⁻]
pH + pOH = 14
[H⁺][OH⁻] = 1.0×10⁻¹⁴
Tags
pH
indicators
acids
bases
pH
7.0
pH
7.0
pOH
7.0
[H⁺]
1.0e-7
[OH⁻]
1.0e-7
Classification
Neutral
Common substances:
pH 1: Stomach acid · pH 2.5: Lemon juice
pH 4.5: Coffee · pH 7: Pure water
pH 8.3: Baking soda · pH 10: Milk of magnesia
pH 13: Bleach · pH 14: Drain cleaner