In the use of a universal indicator, red colour is an indication that the substance...

Chemistry

WAEC 2025

In the use of a universal indicator, red colour is an indication that the substance is a

A. concentrated acid
B. concentrated alkali
C. dilute acid
D. dilute base

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Correct Answer: Option A

Explanation

A universal indicator changes colour to represent the pH level of a substance. For instance, a red colour indicates a very low pH (typically 0 to 3), which corresponds to a strong or concentrated acid; for pH 0: Specifically produces a strong red or dark red colour, representing the highest acidity and for indicator Spectrum: the colour moves from red (strong acid) to orange/yellow (weak/dilute acid), green (neutral), and finally blue/purple (bases).

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