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Universal Indicator

Quick Reference
Also Known AspH indicator mixture, wide-range indicator, full-range indicator, rainbow indicator

What is Universal Indicator?

A universal indicator is a mixture of several pH indicators that changes color progressively through the visible spectrum over a wide pH range (typically pH 1–14). By comparing the color of the solution to a standard color chart, the approximate pH can be determined. Common colors: red (pH 1–2), orange/yellow (pH 3–5), green (pH 6–8), blue (pH 9–11), violet/purple (pH 12–14).

Properties & Characteristics

Mixture of: methyl orange, methyl red, bromothymol blue, thymol blue, phenolphthalein (and others). pH range: 1–14. Color at pH 7 (neutral): green. Not precise — gives approximate pH to ±1 unit. Available as solution or pH paper. More precise measurement: pH meter.

Uses & Applications

Approximate pH testing of solutions. Teaching pH concepts in school. Quick quality control checks. Testing soil pH for gardening. Swimming pool pH testing. Household chemical safety assessment. Environmental water quality screening.

Safety Information

Universal indicator solution may contain methanol or ethanol — flammable. The indicator is used to test acids and bases which may be corrosive. Accidental ingestion of strong acid/base indicated by pH is the actual hazard, not the indicator itself.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Universal Indicator
Synonyms pH indicator mixture, wide-range indicator, full-range indicator, rainbow indicator

Frequently Asked Questions

A universal indicator is a mixture of several pH indicators that changes color progressively through the visible spectrum over a wide pH range (typically pH 1–14). By comparing the color of the solution to a standard color chart, the approximate pH can be determined. Common colors: red (pH 1–2), orange/yellow (pH 3–5), green (pH 6–8), blue (pH 9–11), violet/purple (pH 12–14).

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