Universal indicator gives blue colour in a solution. After adding acid, the colour becomes green. What does this mean?
Answer and explanation
Correct answer: The solution changed from basic to nearly neutral
Universal indicator gives a range of colours linked to pH. Blue generally indicates an alkaline solution, whereas green represents a pH close to neutral. Adding acid consumes some hydroxide ions and lowers the pH, moving the colour from blue toward green. Therefore option B is correct. The observation does not by itself prove that the solution became strongly acidic or that only a gas formed.
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What is the correct answer to this question?
The solution changed from basic to nearly neutral
Why is this the correct answer?
Universal indicator gives a range of colours linked to pH. Blue generally indicates an alkaline solution, whereas green represents a pH close to neutral. Adding acid consumes some hydroxide ions and lowers the pH, moving the colour from blue toward green. Therefore option B is correct. The observation does not by itself prove that the solution became strongly acidic or that only a gas formed.
Which subject and chapter does this question cover?
This is a Class 10 Science question. Chapter: Chemical Substances – Nature and Behaviour. Topic: Acids, Bases, and Salts.
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