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Statement-1: m-Methoxyphenol is a strong...

Statement-1: m-Methoxyphenol is a stronger aciid than p-methoxyphenol
Statement-2: Methoxy group +R-effect at both o- and p-positions.

A

Statement-1 is true, statement-2 is true, statement-2 is a correct explanation for statement-1.

B

Statement-1 is true,s tatement-2 is true, statement-2 is not a correct explanation for statement-1.

C

Statement-1 is true, statement-2 is false.

D

Statement-1 is false, statement-2 is true.

Text Solution

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The correct Answer is:
To analyze the statements regarding m-methoxyphenol and p-methoxyphenol, we will evaluate their acidity based on the effects of the methoxy group on the phenolic compounds. ### Step-by-Step Solution: 1. **Understanding the Compounds**: - **m-Methoxyphenol**: The methoxy group (-OCH₃) is located at the meta position relative to the hydroxyl group (-OH). - **p-Methoxyphenol**: The methoxy group is located at the para position relative to the hydroxyl group. 2. **Acidity of Phenols**: - The acidity of phenolic compounds is influenced by the stability of the conjugate base formed after deprotonation (loss of H⁺). - The conjugate base of phenol is the phenoxide ion, which is stabilized by electron-withdrawing groups and destabilized by electron-donating groups. 3. **Effect of the Methoxy Group**: - The methoxy group has a +R (resonance donating) effect and a -I (inductive withdrawing) effect. - In **p-methoxyphenol**, the +R effect of the methoxy group increases the electron density on the aromatic ring, which can destabilize the phenoxide ion due to increased electron-electron repulsion. - In **m-methoxyphenol**, the methoxy group does not have a significant resonance effect on the hydroxyl group. Its -I effect can help stabilize the conjugate base. 4. **Stability of Conjugate Bases**: - The conjugate base of p-methoxyphenol is less stable due to the destabilizing +R effect from the methoxy group. - The conjugate base of m-methoxyphenol is more stable because the -I effect from the methoxy group helps to stabilize the negative charge on the phenoxide ion. 5. **Conclusion on Acidity**: - Since m-methoxyphenol has a more stable conjugate base compared to p-methoxyphenol, it is a stronger acid. - Therefore, **Statement 1** is true: m-Methoxyphenol is a stronger acid than p-Methoxyphenol. 6. **Evaluation of Statement 2**: - Statement 2 claims that the methoxy group has a +R effect at both ortho and para positions. - While this is true, it does not explain why m-methoxyphenol is a stronger acid than p-methoxyphenol. The destabilization of the conjugate base in p-methoxyphenol due to the +R effect is the key factor in determining its acidity. 7. **Final Assessment**: - **Statement 1** is true. - **Statement 2** is true but does not correctly explain Statement 1. - Therefore, the correct conclusion is that Statement 1 is true, and Statement 2 is true but not a correct explanation for Statement 1.

To analyze the statements regarding m-methoxyphenol and p-methoxyphenol, we will evaluate their acidity based on the effects of the methoxy group on the phenolic compounds. ### Step-by-Step Solution: 1. **Understanding the Compounds**: - **m-Methoxyphenol**: The methoxy group (-OCH₃) is located at the meta position relative to the hydroxyl group (-OH). - **p-Methoxyphenol**: The methoxy group is located at the para position relative to the hydroxyl group. ...
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o- and p- nitrophenols are stronger acids than phenol. Explain.

Each question has 5 choices (a) ,(b) ,(c ) (d) and (e ) out of which ONLY ONE is correct. (a) Statement -1 is True, Statement -2 is True , Statement -2 is a correct explanation for Statement -1. (b) Statement -1 is True, Statement -2 is True, Statement -2 is NOT a correct explanation for Statement -1. (C ) Statement -1 is True, Statement -2 is False. (d) Statement -1 is False, Statement -2 is True. (e) Statement -1 and Statement -2 both are False. Statement -1: The o-hydroxy benzoic acid is a stronger acid than o-methoxy benzoic acid. Statement -2: SIR effect of OH is more prominent than O-CH_(3) .

Knowledge Check

  • Assertion: m- Methoxyphenol is a stronger acid than p -methoxyphenol. Reason: Methoxy group exerts +R -effect at both o -and p- positions.

    A
    If both assertion and reason are true and the reason is the correct explanantion of the assertion.
    B
    If both assertion and reason are true but reason is not the correct explanantion of the asseriton.
    C
    If assertion is true but reason is false.
    D
    If assertion if false but reason is ture.
  • Statement-1: Ethyne is stronger acid than ethene. and Statement-2 Introduction of alkyl group activates benzene ring

    A
    Statement-1 is True , Statement-2 is True , Statement-2 is a correct explanation for Statement-2
    B
    Statement-1 is True , Statement-2 is True , Statement-2 is NOT a correct explanation for Statement-2
    C
    Statement-1 is True , Statement-2 is False
    D
    Statement-1 is False , Statement-2 is True
  • p-Nitrophenol is stronger acid than phenol because nitro group is-

    A
    Electron withdrawing
    B
    Electron donating
    C
    Basic
    D
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