Understanding the pH Scale: Acids, Bases, and Indicators
The pH scale measures how acidic or basic a substance is, ranging from 0 (very acidic) to 14 (very basic), with 7 being neutral.
The formula is: pH = -log₁₀([H⁺]). A change of 1 pH unit means a 10-fold change in hydrogen ion concentration. For example, pH 3 has 10 times more H⁺ than pH 4.
Common pH values: Lemon juice (2.0), Vinegar (2.5), Coffee (5.0), Pure water (7.0), Baking soda (8.3), Soap (9.5), Bleach (12.5).
You can make a natural pH indicator at home using red cabbage. Blend red cabbage with water, strain the liquid, and add a few drops to any solution. Acids turn it red/pink, bases turn it green/yellow.
pH + pOH = 14 (at 25°C). So if you know the pH, you can calculate pOH and vice versa. [H⁺] × [OH⁻] = 10⁻¹⁴ (water dissociation constant).
Use our pH Calculator in the Chemistry category to calculate pH from [H⁺] or vice versa, along with pOH and [OH⁻].