What colour does turmeric become in contact with a basic substance?
Answer and explanation
Correct answer: Reddish-brown
Turmeric contains curcumin, which acts as a natural acid-base indicator. It normally appears yellow, but in contact with a basic substance it changes to a reddish-brown colour because the alkaline medium changes the indicator form of curcumin. Hence option B is correct. The unchanged yellow colour is not the positive test for a base, and blue or green are not the characteristic turmeric response.
Frequently asked questions
What is the correct answer to this question?
Reddish-brown
Why is this the correct answer?
Turmeric contains curcumin, which acts as a natural acid-base indicator. It normally appears yellow, but in contact with a basic substance it changes to a reddish-brown colour because the alkaline medium changes the indicator form of curcumin. Hence option B is correct. The unchanged yellow colour is not the positive test for a base, and blue or green are not the characteristic turmeric response.
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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