acid-base indicator
- noun
- /ˈæsɪd-beɪs ˌɪndɪˈkeɪtər/
- Specialized
- Litmus is a common acid-base indicator used in chemistry laboratories.
Examples
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An acid-base indicator is essential for performing accurate titrations in experiments.
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You should add a few drops of acid-base indicator to see if the solution is acidic or basic.
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The acid-base indicator turned pink in the acidic solution.
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An acid-base indicator helps determine the pH level.
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Litmus paper is a common acid-base indicator that turns red in acidic solutions and blue in basic solutions.
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To test the pH of the solution, we used an acid-base indicator that changed color when immersed.
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The scientist explained how the acid-base indicator helps identify the acidity or alkalinity of various liquids.
Surface Forms
Morphology
acid-base + indicator
The phrase is transparently compositional: an 'indicator' that relates to 'acid' and 'base' conditions, i.e. a chemical that shows whether a solution is acidic or basic (by changing color). This follows a standard noun–modifier pattern and is paralleled in many languages, so a B1 learner who knows the parts would readily infer the meaning.
Etymology
The noun acid-base indicator comes from a simple image: a small indicator that changes color in a liquid to show whether it is 'acid' or 'base'. That's why the name means a chemical that changes color to tell you if a liquid is acidic or basic.