Which of the following compound gives pink colour on reaction with phthalic anhydride in conc. H_2SO_4 followed by treatment with NaOH ?

Alcohols Phenols and Ethers PYQ — JEE Main 2021 · 24 Feb · Shift 1 · Q6 with Solution

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Correct answer: C

Identify the test described

The reaction of a compound with phthalic anhydride in concentrated $H_2SO_4$ , followed by treatment with $NaOH$ , is the phthalein dye test.

In this test, phenols condense with phthalic anhydride in acidic medium to form phthalein dyes.
Colour formed in this test
- Phenol gives phenolphthalein.
- Phenolphthalein is colourless in acidic medium but gives a pink colour in alkaline medium.
Since the question says that after reaction the product is treated with $NaOH$ , we are looking for the compound that forms phenolphthalein, i.e. phenol.
Conclusion

Therefore, the compound that gives pink colour in this test is phenol.
Comparison with stored answer

The stored correct answer is C. This matches the standard result if option C is phenol.

Hence, the derived answer is C.

View written solutionFree

Correct answer: C

Identify the test described

The reaction of a compound with phthalic anhydride in concentrated $H_2SO_4$ , followed by treatment with $NaOH$ , is the phthalein dye test.

In this test, phenols condense with phthalic anhydride in acidic medium to form phthalein dyes.
Colour formed in this test
- Phenol gives phenolphthalein.
- Phenolphthalein is colourless in acidic medium but gives a pink colour in alkaline medium.
Since the question says that after reaction the product is treated with $NaOH$ , we are looking for the compound that forms phenolphthalein, i.e. phenol.
Conclusion

Therefore, the compound that gives pink colour in this test is phenol.
Comparison with stored answer

The stored correct answer is C. This matches the standard result if option C is phenol.

Hence, the derived answer is C.