If turmeric turns reddish-brown and phenolphthalein turns pink in a solution, what is the nature of the solution?
Answer and explanation
Correct answer: Basic
The governing concept is the colour response of acid–base indicators. Turmeric changes to reddish-brown in a basic medium, and phenolphthalein is colourless in acidic or neutral conditions but turns pink in a basic solution. Since both independent observations indicate alkalinity, option B is correct. An acidic solution would not produce this pair of changes, neutrality would keep phenolphthalein colourless, and “gaseous” describes a state of matter rather than the chemical nature shown by the indicators.
Frequently asked questions
What is the correct answer to this question?
Basic
Why is this the correct answer?
The governing concept is the colour response of acid–base indicators. Turmeric changes to reddish-brown in a basic medium, and phenolphthalein is colourless in acidic or neutral conditions but turns pink in a basic solution. Since both independent observations indicate alkalinity, option B is correct. An acidic solution would not produce this pair of changes, neutrality would keep phenolphthalein colourless, and “gaseous” describes a state of matter rather than the chemical nature shown by the indicators.
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.
