A turmeric stain becomes reddish brown when soap is applied. This indicates which nature of soap?
Answer and explanation
Correct answer: Basic nature
Turmeric is a natural acid-base indicator. Its yellow colour changes to reddish brown in a basic or alkaline medium. Since soap solution generally contains alkaline substances formed from a fatty acid and a strong base, it produces this colour change. Therefore, option B is correct. An acidic or neutral solution would not normally turn turmeric reddish brown, while metallic nature is unrelated to indicator behaviour. The substance should be tested safely rather than tasted or rubbed directly.
Frequently asked questions
What is the correct answer to this question?
Basic nature
Why is this the correct answer?
Turmeric is a natural acid-base indicator. Its yellow colour changes to reddish brown in a basic or alkaline medium. Since soap solution generally contains alkaline substances formed from a fatty acid and a strong base, it produces this colour change. Therefore, option B is correct. An acidic or neutral solution would not normally turn turmeric reddish brown, while metallic nature is unrelated to indicator behaviour. The substance should be tested safely rather than tasted or rubbed directly.
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.
