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Assertion (A) Phenol forms 2, 4, 6-tribr...

Assertion (A) Phenol forms 2, 4, 6-tribromophenol o treatement with `Br_(2)` in carbon disulphide at 273K.
Reason (R) Bromine polarises in carbon disulphide.

A

if both assertioon and reason are true and reason is the corrct explanation of assertion.

B

If both assertion and reason are ture but reason is not the corrcet explanation of assertion.

C

If assertion is true but reason is false .

D

if both assertion and reason are false.

Text Solution

AI Generated Solution

The correct Answer is:
To solve the question, we will analyze both the assertion (A) and the reason (R) provided. ### Step-by-Step Solution: 1. **Understanding the Assertion (A)**: - The assertion states that phenol forms 2, 4, 6-tribromophenol when treated with Br₂ in carbon disulfide at 273 K. - Phenol is a compound that has a hydroxyl (-OH) group attached to a benzene ring. This -OH group is an activating group and directs electrophilic substitution to the ortho and para positions of the benzene ring. 2. **Electrophilic Substitution Reaction**: - When phenol reacts with bromine (Br₂), it undergoes electrophilic aromatic substitution. The presence of the -OH group enhances the reactivity of the aromatic ring towards electrophiles like bromine. - In this case, the reaction with Br₂ in carbon disulfide (CS₂) leads to the bromination of phenol. 3. **Product Formation**: - The bromination of phenol will predominantly yield 2-bromophenol and 4-bromophenol due to the directing effects of the -OH group. However, under certain conditions, such as in the presence of excess bromine, 2, 4, 6-tribromophenol can be formed. - Therefore, the assertion is **true**. 4. **Understanding the Reason (R)**: - The reason states that bromine polarizes in carbon disulfide. - In general, bromine (Br₂) is a non-polar molecule. However, in a polar solvent, it can become polarized, allowing it to act as an electrophile. 5. **Solvent Effects**: - Carbon disulfide (CS₂) is a non-polar solvent. In non-polar solvents, bromine does not significantly polarize, which means it does not enhance its electrophilic character as it would in a polar solvent. - Therefore, the reason is **false**. 6. **Conclusion**: - Since the assertion is true and the reason is false, the correct answer is that the assertion is true, but the reason is not a valid explanation for the assertion. ### Final Answer: - Assertion (A) is true. - Reason (R) is false. - Therefore, the correct option is: **A is true, R is false.**
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