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प्रश्न
Compare acidity of phenol with that of ethanol.
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उत्तर १
Phenol is more acidic than ethanol. This is because the phenoxide ion obtained after the release of a proton from phenol becomes stable through resonance, whereas the ethoxide ion (after the release of a proton from ethanol) is not stable.
उत्तर २
Compared with ethanol, phenols are more acidic. They lose their H atom as H+ more readily than alcohols. The behaviour of phenol can be attributed to resonance stabilisation arising from the contributing structures of the corresponding phenoxide ion.
The resonance stabilisation from the contributing structures (I)-(V) sufficiently offsets the O–H bond dissociation energy, rendering phenol acidic.
No resonance structures exist for the ethoxide ion; hence, the conversion of ethanol to ethoxide is not encouraged under standard conditions. Therefore, ethanol exhibits lower acidity compared to phenol.
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संबंधित प्रश्न
Give the structure of the product you would expect when the following alcohol reacts with HCl–ZnCl2.
Butan-1-ol
Account for the following:
o-nitrophenol is more steam volatile than p-nitrophenol.
The product obtained from the reaction is:
Intermolecular hydrogen bonding is strongest in ______.
Phenols do not react with one of the following:
Phenol is more acidic than alcohol because ____________.
Phenol reacts with Br2 in CS2 at low temperature to give ____________.
Arrange the following in decreasing order of acidic character:
What is the correct order of reactivity of alcohols in the following reaction?
\[\ce{R-OH + HCl ->[ZnCl2] R-Cl + H2O}\]
Mark the correct order of decreasing acid strength of the following compounds.
| (a) |  |
| (b) |  |
| (c) |  |
| (d) |  |
| (e) |  |
Assertion: o-Nitrophenol is less soluble in water than the m- and p-isomers.
Reason: m- and p- Nitrophenols exist as associated molecules.
Arrange the following in the increasing order of their property indicated:
4-Nitrobenzoic acid, benzoic acid, 3,4-Dinitrobenzoic acid, 4-Methoxy benzoic acid (Acid strength)
Which is the final product ‘A’ (major) in the given reaction?
Which one of the following has the lowest pKa value?
For the pair phenol and cyclohexanol, answer the following:
Why is phenol more acidic than cyclohexanol?
Give the structure of the product you would expect when the following alcohol reacts with HCl–ZnCl2.
2-Methylbutan-2-ol
Give the structure of the product you would expect when the following alcohol reacts with HBr.
2-Methylbutan-2-ol
