Chemistry · Alcohols, phenols and ethers · chapter 7 of 10

Class 12 Chemistry Chapter 7: Alcohols, Phenols and Ethers Assertion-reason questions with answers

2 assertion-reason questions on Alcohols, Phenols and Ethers, each with its answer and the reason, written from the NCERT chapter. For the CBSE board, JEE Main and NEET, which are set from the same NCERT chapter. Open a question's solution to check your working; then take the free test to find your next chapter. Each question gives an Assertion (A) and a Reason (R); choose how they stand to each other.

Question 1
Assertion (A): Phenol dissolves in aqueous sodium hydroxide, forming sodium phenoxide. Reason (R): Phenol is a stronger acid than water.
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Answer: (a) Both A and R are true, and R is the correct explanation of A.

Both true. Because phenol is a stronger acid than water, it gives up its proton to OH⁻: C₆H₅OH + NaOH → C₆H₅ONa + H₂O. R explains A.

Question 2
Assertion (A): Phenol gives a white precipitate with bromine water without any Lewis acid catalyst. Reason (R): Phenol is a stronger acid than ethanol.
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Answer: (b) Both A and R are true, but R is not the correct explanation of A.

Both true, but the precipitate, 2,4,6-tribromophenol, forms because the strongly activating –OH group lets the bromine molecule polarise and makes the ring very reactive; phenol's acidity is not the reason.

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