Which of the following is a natural indicator for acid and base?
Show answer & explanation
Correct answer: D
Explanation
The Correct Answer is option 4 i.e. China rose.
China rose, also known as Hibiscus rosa-sinensis, is a natural indicator used to detect acids and bases. When its petals are crushed and used to make an indicator solution, it changes color depending on the pH of the substance it is added to. In acidic solutions, the indicator turns bright red, while in basic (alkaline) solutions, it turns greenish or bluish. This property makes it useful in simple chemical experiments to test for acidity or alkalinity using a natural, plant-based source.
Other options :
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Fungi: Not used as acid-base indicators; more relevant in decomposition.
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Curry tree: Used for culinary and medicinal purposes, not as an indicator.
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Algae: Not naturally used for indicating pH changes in common practice.