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1 | 6005-6008 | In the laboratory, phenols are prepared from
benzene derivatives by any of the following methods:
7 4 2
Preparation
of Phenols
The reaction of
Grignard reagents
with methanal
produces a primary
alcohol, with other
aldehydes, secondary
alcohols and with
ketones, tertiary
alcohols (c)
Rationalised 2023-24
202
Chemistry
1 |
1 | 6006-6009 | 4 2
Preparation
of Phenols
The reaction of
Grignard reagents
with methanal
produces a primary
alcohol, with other
aldehydes, secondary
alcohols and with
ketones, tertiary
alcohols (c)
Rationalised 2023-24
202
Chemistry
1 From haloarenes
Chlorobenzene is fused with NaOH at 623K and 320 atmospheric
pressure |
1 | 6007-6010 | 2
Preparation
of Phenols
The reaction of
Grignard reagents
with methanal
produces a primary
alcohol, with other
aldehydes, secondary
alcohols and with
ketones, tertiary
alcohols (c)
Rationalised 2023-24
202
Chemistry
1 From haloarenes
Chlorobenzene is fused with NaOH at 623K and 320 atmospheric
pressure Phenol is obtained by acidification of sodium phenoxide so
produced (Unit 6, Class XII) |
1 | 6008-6011 | (c)
Rationalised 2023-24
202
Chemistry
1 From haloarenes
Chlorobenzene is fused with NaOH at 623K and 320 atmospheric
pressure Phenol is obtained by acidification of sodium phenoxide so
produced (Unit 6, Class XII) 2 |
1 | 6009-6012 | From haloarenes
Chlorobenzene is fused with NaOH at 623K and 320 atmospheric
pressure Phenol is obtained by acidification of sodium phenoxide so
produced (Unit 6, Class XII) 2 From benzenesulphonic acid
Benzene is sulphonated with oleum and benzene sulphonic acid so
formed is converted to sodium phenoxide on heating with molten
sodium hydroxide |
1 | 6010-6013 | Phenol is obtained by acidification of sodium phenoxide so
produced (Unit 6, Class XII) 2 From benzenesulphonic acid
Benzene is sulphonated with oleum and benzene sulphonic acid so
formed is converted to sodium phenoxide on heating with molten
sodium hydroxide Acidification of the sodium salt gives phenol |
1 | 6011-6014 | 2 From benzenesulphonic acid
Benzene is sulphonated with oleum and benzene sulphonic acid so
formed is converted to sodium phenoxide on heating with molten
sodium hydroxide Acidification of the sodium salt gives phenol 3 |
1 | 6012-6015 | From benzenesulphonic acid
Benzene is sulphonated with oleum and benzene sulphonic acid so
formed is converted to sodium phenoxide on heating with molten
sodium hydroxide Acidification of the sodium salt gives phenol 3 From diazonium salts
A diazonium salt is formed by treating an aromatic primary amine
with nitrous acid (NaNO2 + HCl) at 273-278 K |
1 | 6013-6016 | Acidification of the sodium salt gives phenol 3 From diazonium salts
A diazonium salt is formed by treating an aromatic primary amine
with nitrous acid (NaNO2 + HCl) at 273-278 K Diazonium salts are
hydrolysed to phenols by warming with water or by treating with
dilute acids (Unit 9, Class XII) |
1 | 6014-6017 | 3 From diazonium salts
A diazonium salt is formed by treating an aromatic primary amine
with nitrous acid (NaNO2 + HCl) at 273-278 K Diazonium salts are
hydrolysed to phenols by warming with water or by treating with
dilute acids (Unit 9, Class XII) H O
OH
NH2
NaNO2
+HCl
Aniline
N Cl
2
2
N + HCl
2
+
Benzene diazonium
chloride
Warm
+
–
4 |
1 | 6015-6018 | From diazonium salts
A diazonium salt is formed by treating an aromatic primary amine
with nitrous acid (NaNO2 + HCl) at 273-278 K Diazonium salts are
hydrolysed to phenols by warming with water or by treating with
dilute acids (Unit 9, Class XII) H O
OH
NH2
NaNO2
+HCl
Aniline
N Cl
2
2
N + HCl
2
+
Benzene diazonium
chloride
Warm
+
–
4 From cumene
Phenol is manufactured from the hydrocarbon, cumene |
1 | 6016-6019 | Diazonium salts are
hydrolysed to phenols by warming with water or by treating with
dilute acids (Unit 9, Class XII) H O
OH
NH2
NaNO2
+HCl
Aniline
N Cl
2
2
N + HCl
2
+
Benzene diazonium
chloride
Warm
+
–
4 From cumene
Phenol is manufactured from the hydrocarbon, cumene Cumene
(isopropylbenzene) is oxidised in the presence of air to cumene
hydroperoxide |
1 | 6017-6020 | H O
OH
NH2
NaNO2
+HCl
Aniline
N Cl
2
2
N + HCl
2
+
Benzene diazonium
chloride
Warm
+
–
4 From cumene
Phenol is manufactured from the hydrocarbon, cumene Cumene
(isopropylbenzene) is oxidised in the presence of air to cumene
hydroperoxide It is converted to phenol and acetone by treating it
with dilute acid |
1 | 6018-6021 | From cumene
Phenol is manufactured from the hydrocarbon, cumene Cumene
(isopropylbenzene) is oxidised in the presence of air to cumene
hydroperoxide It is converted to phenol and acetone by treating it
with dilute acid Acetone, a by-product of this reaction, is also
obtained in large quantities by this method |
1 | 6019-6022 | Cumene
(isopropylbenzene) is oxidised in the presence of air to cumene
hydroperoxide It is converted to phenol and acetone by treating it
with dilute acid Acetone, a by-product of this reaction, is also
obtained in large quantities by this method Most of the worldwide
production of phenol is
from cumene |
1 | 6020-6023 | It is converted to phenol and acetone by treating it
with dilute acid Acetone, a by-product of this reaction, is also
obtained in large quantities by this method Most of the worldwide
production of phenol is
from cumene Rationalised 2023-24
203
Alcohols, Phenols and Ethers
Alcohols and phenols consist of two parts, an alkyl/aryl group and a
hydroxyl group |
1 | 6021-6024 | Acetone, a by-product of this reaction, is also
obtained in large quantities by this method Most of the worldwide
production of phenol is
from cumene Rationalised 2023-24
203
Alcohols, Phenols and Ethers
Alcohols and phenols consist of two parts, an alkyl/aryl group and a
hydroxyl group The properties of alcohols and phenols are chiefly due
to the hydroxyl group |
1 | 6022-6025 | Most of the worldwide
production of phenol is
from cumene Rationalised 2023-24
203
Alcohols, Phenols and Ethers
Alcohols and phenols consist of two parts, an alkyl/aryl group and a
hydroxyl group The properties of alcohols and phenols are chiefly due
to the hydroxyl group The nature of alkyl and aryl groups simply
modify these properties |
1 | 6023-6026 | Rationalised 2023-24
203
Alcohols, Phenols and Ethers
Alcohols and phenols consist of two parts, an alkyl/aryl group and a
hydroxyl group The properties of alcohols and phenols are chiefly due
to the hydroxyl group The nature of alkyl and aryl groups simply
modify these properties Boiling Points
The boiling points of alcohols and phenols increase with increase in the
number of carbon atoms (increase in van der Waals forces) |
1 | 6024-6027 | The properties of alcohols and phenols are chiefly due
to the hydroxyl group The nature of alkyl and aryl groups simply
modify these properties Boiling Points
The boiling points of alcohols and phenols increase with increase in the
number of carbon atoms (increase in van der Waals forces) In alcohols,
the boiling points decrease with increase of branching in carbon chain
(because of decrease in van der Waals forces with decrease in surface
area) |
1 | 6025-6028 | The nature of alkyl and aryl groups simply
modify these properties Boiling Points
The boiling points of alcohols and phenols increase with increase in the
number of carbon atoms (increase in van der Waals forces) In alcohols,
the boiling points decrease with increase of branching in carbon chain
(because of decrease in van der Waals forces with decrease in surface
area) The –OH group in alcohols and phenols is involved in intermolecular
hydrogen bonding as shown below:
It is interesting to note that boiling points of alcohols and phenols
are higher in comparison to other classes of compounds, namely
hydrocarbons, ethers, haloalkanes and haloarenes of comparable
molecular masses |
1 | 6026-6029 | Boiling Points
The boiling points of alcohols and phenols increase with increase in the
number of carbon atoms (increase in van der Waals forces) In alcohols,
the boiling points decrease with increase of branching in carbon chain
(because of decrease in van der Waals forces with decrease in surface
area) The –OH group in alcohols and phenols is involved in intermolecular
hydrogen bonding as shown below:
It is interesting to note that boiling points of alcohols and phenols
are higher in comparison to other classes of compounds, namely
hydrocarbons, ethers, haloalkanes and haloarenes of comparable
molecular masses For example, ethanol and propane have comparable
molecular masses but their boiling points differ widely |
1 | 6027-6030 | In alcohols,
the boiling points decrease with increase of branching in carbon chain
(because of decrease in van der Waals forces with decrease in surface
area) The –OH group in alcohols and phenols is involved in intermolecular
hydrogen bonding as shown below:
It is interesting to note that boiling points of alcohols and phenols
are higher in comparison to other classes of compounds, namely
hydrocarbons, ethers, haloalkanes and haloarenes of comparable
molecular masses For example, ethanol and propane have comparable
molecular masses but their boiling points differ widely The boiling
point of methoxymethane is intermediate of the two boiling points |
1 | 6028-6031 | The –OH group in alcohols and phenols is involved in intermolecular
hydrogen bonding as shown below:
It is interesting to note that boiling points of alcohols and phenols
are higher in comparison to other classes of compounds, namely
hydrocarbons, ethers, haloalkanes and haloarenes of comparable
molecular masses For example, ethanol and propane have comparable
molecular masses but their boiling points differ widely The boiling
point of methoxymethane is intermediate of the two boiling points 7 |
1 | 6029-6032 | For example, ethanol and propane have comparable
molecular masses but their boiling points differ widely The boiling
point of methoxymethane is intermediate of the two boiling points 7 4 |
1 | 6030-6033 | The boiling
point of methoxymethane is intermediate of the two boiling points 7 4 3
Physical
Properties
7 |
1 | 6031-6034 | 7 4 3
Physical
Properties
7 4
Show how are the following alcohols prepared by the reaction of a suitable
Grignard reagent on methanal |
1 | 6032-6035 | 4 3
Physical
Properties
7 4
Show how are the following alcohols prepared by the reaction of a suitable
Grignard reagent on methanal 7 |
1 | 6033-6036 | 3
Physical
Properties
7 4
Show how are the following alcohols prepared by the reaction of a suitable
Grignard reagent on methanal 7 5
Write structures of the products of the following reactions:
Intext Questions
Intext Questions
Intext Questions
Intext Questions
Intext Questions
(ii)
(iii)
(i)
Rationalised 2023-24
204
Chemistry
The high boiling points of alcohols are mainly due to the presence
of intermolecular hydrogen bonding in them which is lacking in ethers
and hydrocarbons |
1 | 6034-6037 | 4
Show how are the following alcohols prepared by the reaction of a suitable
Grignard reagent on methanal 7 5
Write structures of the products of the following reactions:
Intext Questions
Intext Questions
Intext Questions
Intext Questions
Intext Questions
(ii)
(iii)
(i)
Rationalised 2023-24
204
Chemistry
The high boiling points of alcohols are mainly due to the presence
of intermolecular hydrogen bonding in them which is lacking in ethers
and hydrocarbons Solubility
Solubility of alcohols and phenols in
water is due to their ability to form
hydrogen bonds with water molecules
as shown |
1 | 6035-6038 | 7 5
Write structures of the products of the following reactions:
Intext Questions
Intext Questions
Intext Questions
Intext Questions
Intext Questions
(ii)
(iii)
(i)
Rationalised 2023-24
204
Chemistry
The high boiling points of alcohols are mainly due to the presence
of intermolecular hydrogen bonding in them which is lacking in ethers
and hydrocarbons Solubility
Solubility of alcohols and phenols in
water is due to their ability to form
hydrogen bonds with water molecules
as shown The solubility decreases with
increase in size of alkyl/aryl (hydro-
phobic) groups |
1 | 6036-6039 | 5
Write structures of the products of the following reactions:
Intext Questions
Intext Questions
Intext Questions
Intext Questions
Intext Questions
(ii)
(iii)
(i)
Rationalised 2023-24
204
Chemistry
The high boiling points of alcohols are mainly due to the presence
of intermolecular hydrogen bonding in them which is lacking in ethers
and hydrocarbons Solubility
Solubility of alcohols and phenols in
water is due to their ability to form
hydrogen bonds with water molecules
as shown The solubility decreases with
increase in size of alkyl/aryl (hydro-
phobic) groups Several of the lower
molecular mass alcohols are miscible
with water in all proportions |
1 | 6037-6040 | Solubility
Solubility of alcohols and phenols in
water is due to their ability to form
hydrogen bonds with water molecules
as shown The solubility decreases with
increase in size of alkyl/aryl (hydro-
phobic) groups Several of the lower
molecular mass alcohols are miscible
with water in all proportions Arrange the following sets of compounds in order of their increasing
boiling points:
(a) Pentan-1-ol, butan-1-ol, butan-2-ol, ethanol, propan-1-ol, methanol |
1 | 6038-6041 | The solubility decreases with
increase in size of alkyl/aryl (hydro-
phobic) groups Several of the lower
molecular mass alcohols are miscible
with water in all proportions Arrange the following sets of compounds in order of their increasing
boiling points:
(a) Pentan-1-ol, butan-1-ol, butan-2-ol, ethanol, propan-1-ol, methanol (b) Pentan-1-ol, n-butane, pentanal, ethoxyethane |
1 | 6039-6042 | Several of the lower
molecular mass alcohols are miscible
with water in all proportions Arrange the following sets of compounds in order of their increasing
boiling points:
(a) Pentan-1-ol, butan-1-ol, butan-2-ol, ethanol, propan-1-ol, methanol (b) Pentan-1-ol, n-butane, pentanal, ethoxyethane (a) Methanol, ethanol, propan-1-ol, butan-2-ol, butan-1-ol, pentan-1-ol |
1 | 6040-6043 | Arrange the following sets of compounds in order of their increasing
boiling points:
(a) Pentan-1-ol, butan-1-ol, butan-2-ol, ethanol, propan-1-ol, methanol (b) Pentan-1-ol, n-butane, pentanal, ethoxyethane (a) Methanol, ethanol, propan-1-ol, butan-2-ol, butan-1-ol, pentan-1-ol (b) n-Butane, ethoxyethane, pentanal and pentan-1-ol |
1 | 6041-6044 | (b) Pentan-1-ol, n-butane, pentanal, ethoxyethane (a) Methanol, ethanol, propan-1-ol, butan-2-ol, butan-1-ol, pentan-1-ol (b) n-Butane, ethoxyethane, pentanal and pentan-1-ol Example 7 |
1 | 6042-6045 | (a) Methanol, ethanol, propan-1-ol, butan-2-ol, butan-1-ol, pentan-1-ol (b) n-Butane, ethoxyethane, pentanal and pentan-1-ol Example 7 3
Example 7 |
1 | 6043-6046 | (b) n-Butane, ethoxyethane, pentanal and pentan-1-ol Example 7 3
Example 7 3
Example 7 |
1 | 6044-6047 | Example 7 3
Example 7 3
Example 7 3
Example 7 |
1 | 6045-6048 | 3
Example 7 3
Example 7 3
Example 7 3
Example 7 |
1 | 6046-6049 | 3
Example 7 3
Example 7 3
Example 7 3
Solution
Solution
Solution
Solution
Solution
Alcohols are versatile compounds |
1 | 6047-6050 | 3
Example 7 3
Example 7 3
Solution
Solution
Solution
Solution
Solution
Alcohols are versatile compounds They react both as nucleophiles and
electrophiles |
1 | 6048-6051 | 3
Example 7 3
Solution
Solution
Solution
Solution
Solution
Alcohols are versatile compounds They react both as nucleophiles and
electrophiles The bond between O–H is broken when alcohols react as
nucleophiles |
1 | 6049-6052 | 3
Solution
Solution
Solution
Solution
Solution
Alcohols are versatile compounds They react both as nucleophiles and
electrophiles The bond between O–H is broken when alcohols react as
nucleophiles 7 |
1 | 6050-6053 | They react both as nucleophiles and
electrophiles The bond between O–H is broken when alcohols react as
nucleophiles 7 4 |
1 | 6051-6054 | The bond between O–H is broken when alcohols react as
nucleophiles 7 4 4
Chemical
Reactions
Alcohols as nucleophiles (i)
(ii) The bond between C–O is broken when they react as
electrophiles |
1 | 6052-6055 | 7 4 4
Chemical
Reactions
Alcohols as nucleophiles (i)
(ii) The bond between C–O is broken when they react as
electrophiles Protonated alcohols react in this manner |
1 | 6053-6056 | 4 4
Chemical
Reactions
Alcohols as nucleophiles (i)
(ii) The bond between C–O is broken when they react as
electrophiles Protonated alcohols react in this manner Protonated alcohols as electrophiles
Based on the cleavage of O–H and C–O bonds, the reactions
of alcohols and phenols may be divided into two groups:
Rationalised 2023-24
205
Alcohols, Phenols and Ethers
(a) Reactions involving cleavage of O–H bond
1 |
1 | 6054-6057 | 4
Chemical
Reactions
Alcohols as nucleophiles (i)
(ii) The bond between C–O is broken when they react as
electrophiles Protonated alcohols react in this manner Protonated alcohols as electrophiles
Based on the cleavage of O–H and C–O bonds, the reactions
of alcohols and phenols may be divided into two groups:
Rationalised 2023-24
205
Alcohols, Phenols and Ethers
(a) Reactions involving cleavage of O–H bond
1 Acidity of alcohols and phenols
(i) Reaction with metals: Alcohols and phenols react with active
metals such as sodium, potassium and aluminium to yield
corresponding alkoxides/phenoxides and hydrogen |
1 | 6055-6058 | Protonated alcohols react in this manner Protonated alcohols as electrophiles
Based on the cleavage of O–H and C–O bonds, the reactions
of alcohols and phenols may be divided into two groups:
Rationalised 2023-24
205
Alcohols, Phenols and Ethers
(a) Reactions involving cleavage of O–H bond
1 Acidity of alcohols and phenols
(i) Reaction with metals: Alcohols and phenols react with active
metals such as sodium, potassium and aluminium to yield
corresponding alkoxides/phenoxides and hydrogen In addition to this, phenols react with aqueous sodium
hydroxide to form sodium phenoxides |
1 | 6056-6059 | Protonated alcohols as electrophiles
Based on the cleavage of O–H and C–O bonds, the reactions
of alcohols and phenols may be divided into two groups:
Rationalised 2023-24
205
Alcohols, Phenols and Ethers
(a) Reactions involving cleavage of O–H bond
1 Acidity of alcohols and phenols
(i) Reaction with metals: Alcohols and phenols react with active
metals such as sodium, potassium and aluminium to yield
corresponding alkoxides/phenoxides and hydrogen In addition to this, phenols react with aqueous sodium
hydroxide to form sodium phenoxides Sodium phenoxide
+ H O
2
OH
ONa
+
OH
Na
The above reactions show that alcohols and phenols are
acidic in nature |
1 | 6057-6060 | Acidity of alcohols and phenols
(i) Reaction with metals: Alcohols and phenols react with active
metals such as sodium, potassium and aluminium to yield
corresponding alkoxides/phenoxides and hydrogen In addition to this, phenols react with aqueous sodium
hydroxide to form sodium phenoxides Sodium phenoxide
+ H O
2
OH
ONa
+
OH
Na
The above reactions show that alcohols and phenols are
acidic in nature In fact, alcohols and phenols are Brönsted
acids i |
1 | 6058-6061 | In addition to this, phenols react with aqueous sodium
hydroxide to form sodium phenoxides Sodium phenoxide
+ H O
2
OH
ONa
+
OH
Na
The above reactions show that alcohols and phenols are
acidic in nature In fact, alcohols and phenols are Brönsted
acids i e |
1 | 6059-6062 | Sodium phenoxide
+ H O
2
OH
ONa
+
OH
Na
The above reactions show that alcohols and phenols are
acidic in nature In fact, alcohols and phenols are Brönsted
acids i e , they can donate a proton to a stronger base (B:) |
1 | 6060-6063 | In fact, alcohols and phenols are Brönsted
acids i e , they can donate a proton to a stronger base (B:) (ii) Acidity of alcohols: The acidic character of alcohols is due to
the polar nature of O–H bond |
1 | 6061-6064 | e , they can donate a proton to a stronger base (B:) (ii) Acidity of alcohols: The acidic character of alcohols is due to
the polar nature of O–H bond An electron-releasing group
(–CH3, –C2H5) increases electron density on oxygen tending to
decrease the polarity of O-H bond |
1 | 6062-6065 | , they can donate a proton to a stronger base (B:) (ii) Acidity of alcohols: The acidic character of alcohols is due to
the polar nature of O–H bond An electron-releasing group
(–CH3, –C2H5) increases electron density on oxygen tending to
decrease the polarity of O-H bond This decreases the acid
strength |
1 | 6063-6066 | (ii) Acidity of alcohols: The acidic character of alcohols is due to
the polar nature of O–H bond An electron-releasing group
(–CH3, –C2H5) increases electron density on oxygen tending to
decrease the polarity of O-H bond This decreases the acid
strength For this reason, the acid strength of alcohols decreases
in the following order:
Rationalised 2023-24
206
Chemistry
Alcohols are, however, weaker acids than water |
1 | 6064-6067 | An electron-releasing group
(–CH3, –C2H5) increases electron density on oxygen tending to
decrease the polarity of O-H bond This decreases the acid
strength For this reason, the acid strength of alcohols decreases
in the following order:
Rationalised 2023-24
206
Chemistry
Alcohols are, however, weaker acids than water This can be
illustrated by the reaction of water with an alkoxide |
1 | 6065-6068 | This decreases the acid
strength For this reason, the acid strength of alcohols decreases
in the following order:
Rationalised 2023-24
206
Chemistry
Alcohols are, however, weaker acids than water This can be
illustrated by the reaction of water with an alkoxide This reaction shows that water is a better proton donor (i |
1 | 6066-6069 | For this reason, the acid strength of alcohols decreases
in the following order:
Rationalised 2023-24
206
Chemistry
Alcohols are, however, weaker acids than water This can be
illustrated by the reaction of water with an alkoxide This reaction shows that water is a better proton donor (i e |
1 | 6067-6070 | This can be
illustrated by the reaction of water with an alkoxide This reaction shows that water is a better proton donor (i e ,
stronger acid) than alcohol |
1 | 6068-6071 | This reaction shows that water is a better proton donor (i e ,
stronger acid) than alcohol Also, in the above reaction, we note
that an alkoxide ion is a better proton acceptor than hydroxide
ion, which suggests that alkoxides are stronger bases (sodium
ethoxide is a stronger base than sodium hydroxide) |
1 | 6069-6072 | e ,
stronger acid) than alcohol Also, in the above reaction, we note
that an alkoxide ion is a better proton acceptor than hydroxide
ion, which suggests that alkoxides are stronger bases (sodium
ethoxide is a stronger base than sodium hydroxide) Alcohols act as Bronsted bases as well |
1 | 6070-6073 | ,
stronger acid) than alcohol Also, in the above reaction, we note
that an alkoxide ion is a better proton acceptor than hydroxide
ion, which suggests that alkoxides are stronger bases (sodium
ethoxide is a stronger base than sodium hydroxide) Alcohols act as Bronsted bases as well It is due to the
presence of unshared electron pairs on oxygen, which makes
them proton acceptors |
1 | 6071-6074 | Also, in the above reaction, we note
that an alkoxide ion is a better proton acceptor than hydroxide
ion, which suggests that alkoxides are stronger bases (sodium
ethoxide is a stronger base than sodium hydroxide) Alcohols act as Bronsted bases as well It is due to the
presence of unshared electron pairs on oxygen, which makes
them proton acceptors (iii) Acidity of phenols: The reactions of phenol with metals (e |
1 | 6072-6075 | Alcohols act as Bronsted bases as well It is due to the
presence of unshared electron pairs on oxygen, which makes
them proton acceptors (iii) Acidity of phenols: The reactions of phenol with metals (e g |
1 | 6073-6076 | It is due to the
presence of unshared electron pairs on oxygen, which makes
them proton acceptors (iii) Acidity of phenols: The reactions of phenol with metals (e g ,
sodium, aluminium) and sodium hydroxide indicate its acidic
nature |
1 | 6074-6077 | (iii) Acidity of phenols: The reactions of phenol with metals (e g ,
sodium, aluminium) and sodium hydroxide indicate its acidic
nature The hydroxyl group, in phenol is directly attached to
the sp
2 hybridised carbon of benzene ring which acts as an
electron withdrawing group |
1 | 6075-6078 | g ,
sodium, aluminium) and sodium hydroxide indicate its acidic
nature The hydroxyl group, in phenol is directly attached to
the sp
2 hybridised carbon of benzene ring which acts as an
electron withdrawing group Due to this, the charge distribution
in phenol molecule, as depicted in its resonance structures,
causes the oxygen of –OH group to be positive |
1 | 6076-6079 | ,
sodium, aluminium) and sodium hydroxide indicate its acidic
nature The hydroxyl group, in phenol is directly attached to
the sp
2 hybridised carbon of benzene ring which acts as an
electron withdrawing group Due to this, the charge distribution
in phenol molecule, as depicted in its resonance structures,
causes the oxygen of –OH group to be positive The reaction of phenol with aqueous sodium hydroxide
indicates that phenols are stronger acids than alcohols and water |
1 | 6077-6080 | The hydroxyl group, in phenol is directly attached to
the sp
2 hybridised carbon of benzene ring which acts as an
electron withdrawing group Due to this, the charge distribution
in phenol molecule, as depicted in its resonance structures,
causes the oxygen of –OH group to be positive The reaction of phenol with aqueous sodium hydroxide
indicates that phenols are stronger acids than alcohols and water Let us examine how a compound in which hydroxyl group
attached to an aromatic ring is more acidic than the one in
which hydroxyl group is attached to an alkyl group |
1 | 6078-6081 | Due to this, the charge distribution
in phenol molecule, as depicted in its resonance structures,
causes the oxygen of –OH group to be positive The reaction of phenol with aqueous sodium hydroxide
indicates that phenols are stronger acids than alcohols and water Let us examine how a compound in which hydroxyl group
attached to an aromatic ring is more acidic than the one in
which hydroxyl group is attached to an alkyl group The ionisation of an alcohol and a phenol takes place as follows:
Due to the higher electronegativity of sp
2 hybridised carbon
of phenol to which –OH is attached, electron density decreases
on oxygen |
1 | 6079-6082 | The reaction of phenol with aqueous sodium hydroxide
indicates that phenols are stronger acids than alcohols and water Let us examine how a compound in which hydroxyl group
attached to an aromatic ring is more acidic than the one in
which hydroxyl group is attached to an alkyl group The ionisation of an alcohol and a phenol takes place as follows:
Due to the higher electronegativity of sp
2 hybridised carbon
of phenol to which –OH is attached, electron density decreases
on oxygen This increases the polarity of O–H bond and results
in an increase in ionisation of phenols than that of alcohols |
1 | 6080-6083 | Let us examine how a compound in which hydroxyl group
attached to an aromatic ring is more acidic than the one in
which hydroxyl group is attached to an alkyl group The ionisation of an alcohol and a phenol takes place as follows:
Due to the higher electronegativity of sp
2 hybridised carbon
of phenol to which –OH is attached, electron density decreases
on oxygen This increases the polarity of O–H bond and results
in an increase in ionisation of phenols than that of alcohols Now let us examine the stabilities of alkoxide and phenoxide
ions |
1 | 6081-6084 | The ionisation of an alcohol and a phenol takes place as follows:
Due to the higher electronegativity of sp
2 hybridised carbon
of phenol to which –OH is attached, electron density decreases
on oxygen This increases the polarity of O–H bond and results
in an increase in ionisation of phenols than that of alcohols Now let us examine the stabilities of alkoxide and phenoxide
ions In alkoxide ion, the negative charge is localised on oxygen
while in phenoxide ion, the charge is delocalised |
1 | 6082-6085 | This increases the polarity of O–H bond and results
in an increase in ionisation of phenols than that of alcohols Now let us examine the stabilities of alkoxide and phenoxide
ions In alkoxide ion, the negative charge is localised on oxygen
while in phenoxide ion, the charge is delocalised The delocalisation of negative charge (structures I-V) makes
Rationalised 2023-24
207
Alcohols, Phenols and Ethers
phenoxide ion more stable and favours the ionisation of phenol |
1 | 6083-6086 | Now let us examine the stabilities of alkoxide and phenoxide
ions In alkoxide ion, the negative charge is localised on oxygen
while in phenoxide ion, the charge is delocalised The delocalisation of negative charge (structures I-V) makes
Rationalised 2023-24
207
Alcohols, Phenols and Ethers
phenoxide ion more stable and favours the ionisation of phenol Although there is also charge delocalisation in phenol, its
resonance structures have charge separation due to which the
phenol molecule is less stable than phenoxide ion |
1 | 6084-6087 | In alkoxide ion, the negative charge is localised on oxygen
while in phenoxide ion, the charge is delocalised The delocalisation of negative charge (structures I-V) makes
Rationalised 2023-24
207
Alcohols, Phenols and Ethers
phenoxide ion more stable and favours the ionisation of phenol Although there is also charge delocalisation in phenol, its
resonance structures have charge separation due to which the
phenol molecule is less stable than phenoxide ion o-Nitrophenol
o–O2N–C6H4–OH
7 |
1 | 6085-6088 | The delocalisation of negative charge (structures I-V) makes
Rationalised 2023-24
207
Alcohols, Phenols and Ethers
phenoxide ion more stable and favours the ionisation of phenol Although there is also charge delocalisation in phenol, its
resonance structures have charge separation due to which the
phenol molecule is less stable than phenoxide ion o-Nitrophenol
o–O2N–C6H4–OH
7 2
m-Nitrophenol
m–O2N–C6H4–OH
8 |
1 | 6086-6089 | Although there is also charge delocalisation in phenol, its
resonance structures have charge separation due to which the
phenol molecule is less stable than phenoxide ion o-Nitrophenol
o–O2N–C6H4–OH
7 2
m-Nitrophenol
m–O2N–C6H4–OH
8 3
p-Nitrophenol
p-O2N–C6H4–OH
7 |
1 | 6087-6090 | o-Nitrophenol
o–O2N–C6H4–OH
7 2
m-Nitrophenol
m–O2N–C6H4–OH
8 3
p-Nitrophenol
p-O2N–C6H4–OH
7 1
Phenol
C6H5–OH
10 |
1 | 6088-6091 | 2
m-Nitrophenol
m–O2N–C6H4–OH
8 3
p-Nitrophenol
p-O2N–C6H4–OH
7 1
Phenol
C6H5–OH
10 0
o-Cresol
o-CH3–C6H4–OH
10 |
1 | 6089-6092 | 3
p-Nitrophenol
p-O2N–C6H4–OH
7 1
Phenol
C6H5–OH
10 0
o-Cresol
o-CH3–C6H4–OH
10 2
m-Cresol
m-CH3C6H4–OH
10 |
1 | 6090-6093 | 1
Phenol
C6H5–OH
10 0
o-Cresol
o-CH3–C6H4–OH
10 2
m-Cresol
m-CH3C6H4–OH
10 1
p-Cresol
p-CH3–C6H4–OH
10 |
1 | 6091-6094 | 0
o-Cresol
o-CH3–C6H4–OH
10 2
m-Cresol
m-CH3C6H4–OH
10 1
p-Cresol
p-CH3–C6H4–OH
10 2
Ethanol
C2H5OH
15 |
1 | 6092-6095 | 2
m-Cresol
m-CH3C6H4–OH
10 1
p-Cresol
p-CH3–C6H4–OH
10 2
Ethanol
C2H5OH
15 9
Table 7 |
1 | 6093-6096 | 1
p-Cresol
p-CH3–C6H4–OH
10 2
Ethanol
C2H5OH
15 9
Table 7 3: pKa Values of some Phenols and Ethanol
Compound
Formula
pKa
From the above data, you will note that phenol is million times
more acidic than ethanol |
1 | 6094-6097 | 2
Ethanol
C2H5OH
15 9
Table 7 3: pKa Values of some Phenols and Ethanol
Compound
Formula
pKa
From the above data, you will note that phenol is million times
more acidic than ethanol Arrange the following compounds in increasing order of their acid strength:
Propan-1-ol, 2,4,6-trinitrophenol, 3-nitrophenol, 3,5-dinitrophenol,
phenol, 4-methylphenol |
1 | 6095-6098 | 9
Table 7 3: pKa Values of some Phenols and Ethanol
Compound
Formula
pKa
From the above data, you will note that phenol is million times
more acidic than ethanol Arrange the following compounds in increasing order of their acid strength:
Propan-1-ol, 2,4,6-trinitrophenol, 3-nitrophenol, 3,5-dinitrophenol,
phenol, 4-methylphenol Propan-1-ol, 4-methylphenol, phenol, 3-nitrophenol, 3,5-dinitrophenol,
2,4, 6-trinitrophenol |
1 | 6096-6099 | 3: pKa Values of some Phenols and Ethanol
Compound
Formula
pKa
From the above data, you will note that phenol is million times
more acidic than ethanol Arrange the following compounds in increasing order of their acid strength:
Propan-1-ol, 2,4,6-trinitrophenol, 3-nitrophenol, 3,5-dinitrophenol,
phenol, 4-methylphenol Propan-1-ol, 4-methylphenol, phenol, 3-nitrophenol, 3,5-dinitrophenol,
2,4, 6-trinitrophenol Example 7 |
1 | 6097-6100 | Arrange the following compounds in increasing order of their acid strength:
Propan-1-ol, 2,4,6-trinitrophenol, 3-nitrophenol, 3,5-dinitrophenol,
phenol, 4-methylphenol Propan-1-ol, 4-methylphenol, phenol, 3-nitrophenol, 3,5-dinitrophenol,
2,4, 6-trinitrophenol Example 7 4
Example 7 |
1 | 6098-6101 | Propan-1-ol, 4-methylphenol, phenol, 3-nitrophenol, 3,5-dinitrophenol,
2,4, 6-trinitrophenol Example 7 4
Example 7 4
Example 7 |
1 | 6099-6102 | Example 7 4
Example 7 4
Example 7 4
Example 7 |
1 | 6100-6103 | 4
Example 7 4
Example 7 4
Example 7 4
Example 7 |
1 | 6101-6104 | 4
Example 7 4
Example 7 4
Example 7 4
Solution
Solution
Solution
Solution
Solution
2 |
1 | 6102-6105 | 4
Example 7 4
Example 7 4
Solution
Solution
Solution
Solution
Solution
2 Esterification
Alcohols and phenols react with carboxylic acids, acid chlorides and
acid anhydrides to form esters |
1 | 6103-6106 | 4
Example 7 4
Solution
Solution
Solution
Solution
Solution
2 Esterification
Alcohols and phenols react with carboxylic acids, acid chlorides and
acid anhydrides to form esters In substituted phenols, the presence of electron withdrawing
groups such as nitro group, enhances the acidic strength of
phenol |
1 | 6104-6107 | 4
Solution
Solution
Solution
Solution
Solution
2 Esterification
Alcohols and phenols react with carboxylic acids, acid chlorides and
acid anhydrides to form esters In substituted phenols, the presence of electron withdrawing
groups such as nitro group, enhances the acidic strength of
phenol This effect is more pronounced when such a group is
present at ortho and para positions |
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