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कर्नाटक बोर्ड पी.यू.सी.पीयूसी विज्ञान 2nd PUC Class 12

In Kolbe’s reaction, instead of phenol, phenoxide ion is treated with carbon dioxide. Why? - Chemistry

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प्रश्न

In Kolbe’s reaction, instead of phenol, phenoxide ion is treated with carbon dioxide. Why?

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उत्तर

Phenoxide ion is more reactive than phenol towards electrophilic substitution. The negative charge on oxygen is transferred to benzene through resonance. This helps in the attachment of CO2 which is a weak electrophile to the benzene ring finally giving salicylic acid.

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पाठ 11: Alcohols, Phenols and Ethers - Multiple Choice Questions (Type - I) [पृष्ठ १६०]

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एनसीईआरटी एक्झांप्लर Chemistry [English] Class 12
पाठ 11 Alcohols, Phenols and Ethers
Multiple Choice Questions (Type - I) | Q 48 | पृष्ठ १६०

संबंधित प्रश्‍न

Write the mechanism of the following reaction:


Write the mechanism of the following reaction :


Write the mechanism of the following reaction :


Give the equation of the following reaction: 

Dilute HNO3 with phenol.


Give the equation of the following reaction: 

Treating phenol with chloroform in the presence of aqueous NaOH.


Name the reagent used in the following reaction:

Oxidation of a primary alcohol to aldehyde.


When 3-methylbutan-2-ol is treated with HBr, the following reaction takes place:

\[\begin{array}{cc}
\phantom{.......................}\ce{Br}\\
\phantom{......................}|\\
\ce{CH3 - CH - CH - CH3 ->[HBr] CH3 - C - CH2 - CH3}\\
\phantom{.}|\phantom{......}|\phantom{......................}|\phantom{........}\\
\phantom{}\ce{CH3}\phantom{...}\ce{OH}\phantom{...................}\ce{CH3}\phantom{.....}
\end{array}\]

Give a mechanism for this reaction.

(Hint: The secondary carbocation formed in step II rearranges to a more

stable tertiary carbocation by a hydride ion shift from 3rd carbon atom.)


Write the mechanism (using curved arrow notation) of the following reaction :


Dehydration of 2-butanol yields:


Lucas test is done to differentiate between ____________.


\[\ce{CH3CH2OH}\] can be converted into \[\ce{CH3CHO}\] by ______.


Identify the secondary alcohols from the following set:

  1. \[\ce{CH3CH2CH(OH)CH3}\]
  2. \[\ce{(C2H5)3COH}\]



Explain why is OH group in phenols more strongly held as compared to OH group in alcohols.


Assertion: Bond angle in ethers is slightly less than the tetrahedral angle.

Reason: There is a repulsion between the two bulky (–R) groups.


The correct geometry around oxygen in CH3OCH3 is 


Write the mechanism of acid dehydration of ethanol to yield ethene.


Write the mechanism of acid dehydration of ethanol to yield ethene.


Write the mechanism of acid dehydration of ethanol to yield ethene.


Write the mechanism of acid-catalysed dehydration of ethanol to yield ethene.


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