Cambridge O Level Chemistry · Syllabus 5070 · Acids, Bases and Salts
Universal Indicator
What is Universal Indicator?
A mixture of indicators that shows a range of colours across the pH scale rather than a single change, so it can be used to estimate pH and to compare how acidic or how alkaline two solutions are. It is red or orange in strongly acidic solution, green at about pH 7, and blue or purple in strongly alkaline solution.
This definition is part of the Acids, Bases and Salts chapter in Cambridge O Level Chemistry.
Common mistakes with Universal Indicator
- “Universal indicator just tells you acid or alkali.” Repair Litmus does that. Universal indicator gives a graded colour, so it lets you compare how acidic or alkaline two solutions are, and match the colour to an approximate pH. That is what statement 7.1.12 is asking for.
Reviewed by Academiq Edu Instructor PanelLast reviewed Syllabus 2026-2028