323291
Which one of the following compounds would undergo nitration with greatest ease?
1 Benzene
2 Phenol
3 Nitrobenzene
4 Benzoic acid
Explanation:
\(\mathrm{pK}_{\mathrm{a}}\) of phenol is 10
CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323292
Assertion : Like bromination of benzene, bromination of phenol is also carried out in the presence of Lewis acid. Reason : Lewis acid polarises the bromine molecule.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but Reason is correct.
Explanation:
Conceptual Questions
CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323293
At low temperature, phenol reacts with \(\mathrm{Br}_{2}\) in \(\mathrm{CS}_{2}\) to form
1 m-bromophenol
2 o and p-bromophenol
3 p-bromophenol
4 2,4,6-tribromophenol
Explanation:
In the presence of non-polar solvent \(\left(\mathrm{CS}_{2}\right)\), the ionisation of phenol is suppressed. The ring is slightly activated and hence, mono substitution occurs. Low temperature favours the formation of p-product.
CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323294
Assertion : Phenol is more reactive than benzene towards electrophilic substitution reaction. Reason : In the case of phenol, the intermediate carbocation is more resonance stabilised.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but Reason is correct.
Explanation:
The \(-\mathrm{OH}\) group, attached to the benzene ring, in phenol activates it towards electrophilic substitution and directs the incoming group to the ortho and para positions as these positions become electron rich due to the resonance. In contrast, benzene lacks the electron-donating \(-\mathrm{OH}\) group. As a result, electrophilic aromatic substitution reactions are less efficient and slower in benzene compared to phenol. So the option (1) is correct.
CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323295
Assertion : Phenol forms \(2,4,6\)-tribromophenol on treatment with \(\mathrm{Br}_{2}\) - water at \(273 \mathrm{~K.}\) Reason : Phenol is o / p- directing group.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but Reason is correct.
Explanation:
Phenol forms 2,4,6-Tribromophenol (white \(\mathrm{ppt})\) when treated with \(\mathrm{Br}_{2}\) in water. In phenols, the polarization of the bromine molecule occurs even in the absence of a Lewis acid. This is because phenols are more reactive than benzene due to the presence of the hydroxyl (\(\mathrm{-OH}\) ) group, which activates the ring and makes it more susceptible to electrophilic aromatic substitution reactions. So the option (2) is correct.
323291
Which one of the following compounds would undergo nitration with greatest ease?
1 Benzene
2 Phenol
3 Nitrobenzene
4 Benzoic acid
Explanation:
\(\mathrm{pK}_{\mathrm{a}}\) of phenol is 10
CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323292
Assertion : Like bromination of benzene, bromination of phenol is also carried out in the presence of Lewis acid. Reason : Lewis acid polarises the bromine molecule.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but Reason is correct.
Explanation:
Conceptual Questions
CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323293
At low temperature, phenol reacts with \(\mathrm{Br}_{2}\) in \(\mathrm{CS}_{2}\) to form
1 m-bromophenol
2 o and p-bromophenol
3 p-bromophenol
4 2,4,6-tribromophenol
Explanation:
In the presence of non-polar solvent \(\left(\mathrm{CS}_{2}\right)\), the ionisation of phenol is suppressed. The ring is slightly activated and hence, mono substitution occurs. Low temperature favours the formation of p-product.
CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323294
Assertion : Phenol is more reactive than benzene towards electrophilic substitution reaction. Reason : In the case of phenol, the intermediate carbocation is more resonance stabilised.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but Reason is correct.
Explanation:
The \(-\mathrm{OH}\) group, attached to the benzene ring, in phenol activates it towards electrophilic substitution and directs the incoming group to the ortho and para positions as these positions become electron rich due to the resonance. In contrast, benzene lacks the electron-donating \(-\mathrm{OH}\) group. As a result, electrophilic aromatic substitution reactions are less efficient and slower in benzene compared to phenol. So the option (1) is correct.
CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323295
Assertion : Phenol forms \(2,4,6\)-tribromophenol on treatment with \(\mathrm{Br}_{2}\) - water at \(273 \mathrm{~K.}\) Reason : Phenol is o / p- directing group.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but Reason is correct.
Explanation:
Phenol forms 2,4,6-Tribromophenol (white \(\mathrm{ppt})\) when treated with \(\mathrm{Br}_{2}\) in water. In phenols, the polarization of the bromine molecule occurs even in the absence of a Lewis acid. This is because phenols are more reactive than benzene due to the presence of the hydroxyl (\(\mathrm{-OH}\) ) group, which activates the ring and makes it more susceptible to electrophilic aromatic substitution reactions. So the option (2) is correct.
NEET Test Series from KOTA - 10 Papers In MS WORD
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CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323291
Which one of the following compounds would undergo nitration with greatest ease?
1 Benzene
2 Phenol
3 Nitrobenzene
4 Benzoic acid
Explanation:
\(\mathrm{pK}_{\mathrm{a}}\) of phenol is 10
CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323292
Assertion : Like bromination of benzene, bromination of phenol is also carried out in the presence of Lewis acid. Reason : Lewis acid polarises the bromine molecule.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but Reason is correct.
Explanation:
Conceptual Questions
CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323293
At low temperature, phenol reacts with \(\mathrm{Br}_{2}\) in \(\mathrm{CS}_{2}\) to form
1 m-bromophenol
2 o and p-bromophenol
3 p-bromophenol
4 2,4,6-tribromophenol
Explanation:
In the presence of non-polar solvent \(\left(\mathrm{CS}_{2}\right)\), the ionisation of phenol is suppressed. The ring is slightly activated and hence, mono substitution occurs. Low temperature favours the formation of p-product.
CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323294
Assertion : Phenol is more reactive than benzene towards electrophilic substitution reaction. Reason : In the case of phenol, the intermediate carbocation is more resonance stabilised.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but Reason is correct.
Explanation:
The \(-\mathrm{OH}\) group, attached to the benzene ring, in phenol activates it towards electrophilic substitution and directs the incoming group to the ortho and para positions as these positions become electron rich due to the resonance. In contrast, benzene lacks the electron-donating \(-\mathrm{OH}\) group. As a result, electrophilic aromatic substitution reactions are less efficient and slower in benzene compared to phenol. So the option (1) is correct.
CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323295
Assertion : Phenol forms \(2,4,6\)-tribromophenol on treatment with \(\mathrm{Br}_{2}\) - water at \(273 \mathrm{~K.}\) Reason : Phenol is o / p- directing group.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but Reason is correct.
Explanation:
Phenol forms 2,4,6-Tribromophenol (white \(\mathrm{ppt})\) when treated with \(\mathrm{Br}_{2}\) in water. In phenols, the polarization of the bromine molecule occurs even in the absence of a Lewis acid. This is because phenols are more reactive than benzene due to the presence of the hydroxyl (\(\mathrm{-OH}\) ) group, which activates the ring and makes it more susceptible to electrophilic aromatic substitution reactions. So the option (2) is correct.
323291
Which one of the following compounds would undergo nitration with greatest ease?
1 Benzene
2 Phenol
3 Nitrobenzene
4 Benzoic acid
Explanation:
\(\mathrm{pK}_{\mathrm{a}}\) of phenol is 10
CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323292
Assertion : Like bromination of benzene, bromination of phenol is also carried out in the presence of Lewis acid. Reason : Lewis acid polarises the bromine molecule.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but Reason is correct.
Explanation:
Conceptual Questions
CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323293
At low temperature, phenol reacts with \(\mathrm{Br}_{2}\) in \(\mathrm{CS}_{2}\) to form
1 m-bromophenol
2 o and p-bromophenol
3 p-bromophenol
4 2,4,6-tribromophenol
Explanation:
In the presence of non-polar solvent \(\left(\mathrm{CS}_{2}\right)\), the ionisation of phenol is suppressed. The ring is slightly activated and hence, mono substitution occurs. Low temperature favours the formation of p-product.
CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323294
Assertion : Phenol is more reactive than benzene towards electrophilic substitution reaction. Reason : In the case of phenol, the intermediate carbocation is more resonance stabilised.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but Reason is correct.
Explanation:
The \(-\mathrm{OH}\) group, attached to the benzene ring, in phenol activates it towards electrophilic substitution and directs the incoming group to the ortho and para positions as these positions become electron rich due to the resonance. In contrast, benzene lacks the electron-donating \(-\mathrm{OH}\) group. As a result, electrophilic aromatic substitution reactions are less efficient and slower in benzene compared to phenol. So the option (1) is correct.
CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323295
Assertion : Phenol forms \(2,4,6\)-tribromophenol on treatment with \(\mathrm{Br}_{2}\) - water at \(273 \mathrm{~K.}\) Reason : Phenol is o / p- directing group.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but Reason is correct.
Explanation:
Phenol forms 2,4,6-Tribromophenol (white \(\mathrm{ppt})\) when treated with \(\mathrm{Br}_{2}\) in water. In phenols, the polarization of the bromine molecule occurs even in the absence of a Lewis acid. This is because phenols are more reactive than benzene due to the presence of the hydroxyl (\(\mathrm{-OH}\) ) group, which activates the ring and makes it more susceptible to electrophilic aromatic substitution reactions. So the option (2) is correct.
323291
Which one of the following compounds would undergo nitration with greatest ease?
1 Benzene
2 Phenol
3 Nitrobenzene
4 Benzoic acid
Explanation:
\(\mathrm{pK}_{\mathrm{a}}\) of phenol is 10
CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323292
Assertion : Like bromination of benzene, bromination of phenol is also carried out in the presence of Lewis acid. Reason : Lewis acid polarises the bromine molecule.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but Reason is correct.
Explanation:
Conceptual Questions
CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323293
At low temperature, phenol reacts with \(\mathrm{Br}_{2}\) in \(\mathrm{CS}_{2}\) to form
1 m-bromophenol
2 o and p-bromophenol
3 p-bromophenol
4 2,4,6-tribromophenol
Explanation:
In the presence of non-polar solvent \(\left(\mathrm{CS}_{2}\right)\), the ionisation of phenol is suppressed. The ring is slightly activated and hence, mono substitution occurs. Low temperature favours the formation of p-product.
CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323294
Assertion : Phenol is more reactive than benzene towards electrophilic substitution reaction. Reason : In the case of phenol, the intermediate carbocation is more resonance stabilised.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but Reason is correct.
Explanation:
The \(-\mathrm{OH}\) group, attached to the benzene ring, in phenol activates it towards electrophilic substitution and directs the incoming group to the ortho and para positions as these positions become electron rich due to the resonance. In contrast, benzene lacks the electron-donating \(-\mathrm{OH}\) group. As a result, electrophilic aromatic substitution reactions are less efficient and slower in benzene compared to phenol. So the option (1) is correct.
CHXII11:ALCOHOLS, PHENOLS AND ETHERS
323295
Assertion : Phenol forms \(2,4,6\)-tribromophenol on treatment with \(\mathrm{Br}_{2}\) - water at \(273 \mathrm{~K.}\) Reason : Phenol is o / p- directing group.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but Reason is correct.
Explanation:
Phenol forms 2,4,6-Tribromophenol (white \(\mathrm{ppt})\) when treated with \(\mathrm{Br}_{2}\) in water. In phenols, the polarization of the bromine molecule occurs even in the absence of a Lewis acid. This is because phenols are more reactive than benzene due to the presence of the hydroxyl (\(\mathrm{-OH}\) ) group, which activates the ring and makes it more susceptible to electrophilic aromatic substitution reactions. So the option (2) is correct.
