How does phenolphthalein appear in an acidic solution?
Answer and explanation
Correct answer: Colourless
Phenolphthalein is an acid-base indicator whose colour depends on the pH of the solution. In an acidic medium, its indicator form remains colourless; it becomes pink or magenta only in a sufficiently basic medium. Therefore, the absence of colour identifies the acidic condition in this test. The pink option belongs to the basic response, while blue and green are not the characteristic phenolphthalein colours. Option B is correct.
Frequently asked questions
What is the correct answer to this question?
Colourless
Why is this the correct answer?
Phenolphthalein is an acid-base indicator whose colour depends on the pH of the solution. In an acidic medium, its indicator form remains colourless; it becomes pink or magenta only in a sufficiently basic medium. Therefore, the absence of colour identifies the acidic condition in this test. The pink option belongs to the basic response, while blue and green are not the characteristic phenolphthalein colours. Option B is correct.
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.
