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प्रश्न
The carbon-oxygen bond in phenol is slightly stronger than that in methanol. Why?
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उत्तर
This can be explained as under:
(i) In phenol, the conjugation of unshared electron pairs over oxygen with aromatic ring results in partial double bond character in C – O bond.
In methanol, no such conjugation (resonance) is possible.
(ii) In phenol, oxygen is attached to sp2 hybridised carbon while in methanol, oxygen attached to sp2 hybridised carbon. An sp2 hybridised carbon is more electronegative (because of greater 5-character) than sp3 hybridised carbon atom. Therefore, the bond between oxygen and sp2 hybridised carbon is more stable than the bond between oxygen and sp2, hybridised orbital.
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संबंधित प्रश्न
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\[\begin{array}{cc}
\phantom{.}\ce{CH3 - CH - CH - CH - CH - CH3}\phantom{}\\
\phantom{......}|\phantom{......}|\phantom{......}|\phantom{.....}|\phantom{........}\\
\phantom{...}\ce{CH3}\phantom{...}\ce{OH}\phantom{...}\ce{C2H5}\phantom{.}\ce{OH}\phantom{...}\end{array}\]
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| Column I | Column II | |
| (i) | Antifreeze used in car engine | (a) Neutral ferric chloride |
| (ii) | Solvent used in perfumes | (b) Glycerol |
| (iii) | Starting material for picric acid | (c) Methanol |
| (iv) | Wood spirit | (d) Phenol |
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| Column I | Column II | |
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| (ii) | Kolbe’s reaction | (b) Ethyl alcohol |
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| (iv) | Conversion of 2° alcohol to ketone | (d) Wood spirit |
| (v) | Reimer-Tiemann reaction | (e) Heated copper at 573 K |
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\[\begin{array}{cc}
\ce{CH3 - CH - CH - CH - CH2-OH }\\
|\phantom{......}|\phantom{......}|\phantom{.......}\\
\ce{Cl}\phantom{....}\ce{CH3}\phantom{...}\ce{CH3}\phantom{.....}
\end{array}\]
