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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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संबंधित प्रश्न
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:
\[\begin{array}{cc}
\phantom{...................................}\ce{Br}\\
\phantom{..................................}|\\
\ce{CH3 - CH - CH - CH3 ->[HBr] CH3 - C - CH2 - CH3}\\
|\phantom{.........}|\phantom{...................................}|\phantom{...........}\\
\ce{CH3}\phantom{...}\ce{OH}\phantom{...............................}\ce{CH3}\phantom{.......}\\
\end{array}\]
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.)
Lucas test is used for the detection of _____________.
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(i) H2/Pd
(ii) LiAlH4
(iii) NaBH4
(iv) Reaction with RMgX followed by hydrolysis
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Primary and secondary alcohols on the action of reduced copper give:
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| (a) |  |
| (b) |  |
| (c) |  |
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Reason: There is a repulsion between the two bulky (–R) groups.
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Write the chemical equation in support of your answer.
Write the mechanism of acid-catalysed 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
