Rajasthan BoardEnglish MediumSTD 12 ScienceChemistryAlcohols, Phenols, and Ethers1 Mark
Question
Explain why is $OH$ group in phenols more strongly held as compared to $OH$ group in alcohols.
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Answer
In phenols, the $-OH$ group is attached to $sp^2$ hybridised carbon of an aromatic ring.
The carbon$-$ oxygen bond length $(136\ pm)$ in phenol is slightly less than that in methanol.
This is due to partial double bond character on account of the conjugation of unshared electron pair of oxygen with the aromatic ring whereas in alcohols, the oxygen of the $-OH$ group is attached to carbon by a sigma bond formed by the overlap of a $sp^3$ hybridised orbital of carbon with a $sp^3$ hybridised orbital of oxygen.
That is why $-OH$ group in phenol is more strongly held as compared to alcohol.
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