Science — AI-generated practice question

A universal indicator is a mixture of several indicators that shows different colours at different concentrations of hydrogen ions in a solution.

It is used to measure the pH of a solution (on a scale of 0–14), which indicates how acidic or basic a solution is. It is commonly used in the form of pH paper impregnated with the universal indicator.

Source: Chapter 2, Section 2.3

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• The question is worth 2 marks: one mark for defining universal indicator, one mark for its use.
• Key phrase: "mixture of several indicators" — examiners expect this exact description.
• Mention pH scale (0–14) and that it measures hydrogen ion concentration; this shows understanding of why it is used, not just what it measures.
• Avoid writing about pH importance in everyday life — that goes beyond what the question asks and wastes time.