Chapter
stringclasses 18
values | sentence_range
stringlengths 3
9
| Text
stringlengths 7
7.34k
|
|---|---|---|
1 | 6805-6808 | Mild reaction conditions are used to stop the
reaction at the amide stage 4 From Grignard reagents
Grignard reagents react with carbon dioxide (dry ice) to form salts of
carboxylic acids which in turn give corresponding carboxylic acids
after acidification with mineral acid As we know, the Grignard reagents and nitriles can be prepared
from alkyl halides (refer Unit 6, Class XII) |
1 | 6806-6809 | 4 From Grignard reagents
Grignard reagents react with carbon dioxide (dry ice) to form salts of
carboxylic acids which in turn give corresponding carboxylic acids
after acidification with mineral acid As we know, the Grignard reagents and nitriles can be prepared
from alkyl halides (refer Unit 6, Class XII) The above methods
Rationalised 2023-24
247
Aldehydes, Ketones and Carboxylic Acids
(3 and 4) are useful for converting alkyl halides into corresponding
carboxylic acids having one carbon atom more than that present in
alkyl halides (ascending the series) |
1 | 6807-6810 | From Grignard reagents
Grignard reagents react with carbon dioxide (dry ice) to form salts of
carboxylic acids which in turn give corresponding carboxylic acids
after acidification with mineral acid As we know, the Grignard reagents and nitriles can be prepared
from alkyl halides (refer Unit 6, Class XII) The above methods
Rationalised 2023-24
247
Aldehydes, Ketones and Carboxylic Acids
(3 and 4) are useful for converting alkyl halides into corresponding
carboxylic acids having one carbon atom more than that present in
alkyl halides (ascending the series) 5 |
1 | 6808-6811 | As we know, the Grignard reagents and nitriles can be prepared
from alkyl halides (refer Unit 6, Class XII) The above methods
Rationalised 2023-24
247
Aldehydes, Ketones and Carboxylic Acids
(3 and 4) are useful for converting alkyl halides into corresponding
carboxylic acids having one carbon atom more than that present in
alkyl halides (ascending the series) 5 From acyl halides and anhydrides
Acid chlorides when hydrolysed with water give carboxylic acids or more
readily hydrolysed with aqueous base to give carboxylate ions which on
acidification provide corresponding carboxylic acids |
1 | 6809-6812 | The above methods
Rationalised 2023-24
247
Aldehydes, Ketones and Carboxylic Acids
(3 and 4) are useful for converting alkyl halides into corresponding
carboxylic acids having one carbon atom more than that present in
alkyl halides (ascending the series) 5 From acyl halides and anhydrides
Acid chlorides when hydrolysed with water give carboxylic acids or more
readily hydrolysed with aqueous base to give carboxylate ions which on
acidification provide corresponding carboxylic acids Anhydrides on the
other hand are hydrolysed to corresponding acid(s) with water |
1 | 6810-6813 | 5 From acyl halides and anhydrides
Acid chlorides when hydrolysed with water give carboxylic acids or more
readily hydrolysed with aqueous base to give carboxylate ions which on
acidification provide corresponding carboxylic acids Anhydrides on the
other hand are hydrolysed to corresponding acid(s) with water 6 |
1 | 6811-6814 | From acyl halides and anhydrides
Acid chlorides when hydrolysed with water give carboxylic acids or more
readily hydrolysed with aqueous base to give carboxylate ions which on
acidification provide corresponding carboxylic acids Anhydrides on the
other hand are hydrolysed to corresponding acid(s) with water 6 From esters
Acidic hydrolysis of esters gives directly carboxylic acids while basic
hydrolysis gives carboxylates, which on acidification give
corresponding carboxylic acids |
1 | 6812-6815 | Anhydrides on the
other hand are hydrolysed to corresponding acid(s) with water 6 From esters
Acidic hydrolysis of esters gives directly carboxylic acids while basic
hydrolysis gives carboxylates, which on acidification give
corresponding carboxylic acids Example 8 |
1 | 6813-6816 | 6 From esters
Acidic hydrolysis of esters gives directly carboxylic acids while basic
hydrolysis gives carboxylates, which on acidification give
corresponding carboxylic acids Example 8 5
Example 8 |
1 | 6814-6817 | From esters
Acidic hydrolysis of esters gives directly carboxylic acids while basic
hydrolysis gives carboxylates, which on acidification give
corresponding carboxylic acids Example 8 5
Example 8 5
Example 8 |
1 | 6815-6818 | Example 8 5
Example 8 5
Example 8 5
Example 8 |
1 | 6816-6819 | 5
Example 8 5
Example 8 5
Example 8 5
Example 8 |
1 | 6817-6820 | 5
Example 8 5
Example 8 5
Example 8 5
Write chemical reactions to affect the following transformations:
(i)
Butan-1-ol to butanoic acid
(ii)
Benzyl alcohol to phenylethanoic acid
(iii) 3-Nitrobromobenzene to 3-nitrobenzoic acid
(iv) 4-Methylacetophenone to benzene-1,4-dicarboxylic acid
(v)
Cyclohexene to hexane-1,6-dioic acid
(vi) Butanal to butanoic acid |
1 | 6818-6821 | 5
Example 8 5
Example 8 5
Write chemical reactions to affect the following transformations:
(i)
Butan-1-ol to butanoic acid
(ii)
Benzyl alcohol to phenylethanoic acid
(iii) 3-Nitrobromobenzene to 3-nitrobenzoic acid
(iv) 4-Methylacetophenone to benzene-1,4-dicarboxylic acid
(v)
Cyclohexene to hexane-1,6-dioic acid
(vi) Butanal to butanoic acid Rationalised 2023-24
248
Chemistry
Intext Question
Intext Question
Intext Question
Intext Question
Intext Question
8 |
1 | 6819-6822 | 5
Example 8 5
Write chemical reactions to affect the following transformations:
(i)
Butan-1-ol to butanoic acid
(ii)
Benzyl alcohol to phenylethanoic acid
(iii) 3-Nitrobromobenzene to 3-nitrobenzoic acid
(iv) 4-Methylacetophenone to benzene-1,4-dicarboxylic acid
(v)
Cyclohexene to hexane-1,6-dioic acid
(vi) Butanal to butanoic acid Rationalised 2023-24
248
Chemistry
Intext Question
Intext Question
Intext Question
Intext Question
Intext Question
8 7
Show how each of the following compounds can be
converted to benzoic acid |
1 | 6820-6823 | 5
Write chemical reactions to affect the following transformations:
(i)
Butan-1-ol to butanoic acid
(ii)
Benzyl alcohol to phenylethanoic acid
(iii) 3-Nitrobromobenzene to 3-nitrobenzoic acid
(iv) 4-Methylacetophenone to benzene-1,4-dicarboxylic acid
(v)
Cyclohexene to hexane-1,6-dioic acid
(vi) Butanal to butanoic acid Rationalised 2023-24
248
Chemistry
Intext Question
Intext Question
Intext Question
Intext Question
Intext Question
8 7
Show how each of the following compounds can be
converted to benzoic acid (i)
Ethylbenzene
(ii)
Acetophenone
(iii)
Bromobenzene
(iv)
Phenylethene (Styrene)
Solution
Solution
Solution
Solution
Solution
(i)
(ii)
(iii)
(iv)
(v)
(vi)
Rationalised 2023-24
249
Aldehydes, Ketones and Carboxylic Acids
Aliphatic carboxylic acids upto nine carbon atoms are colourless
liquids at room temperature with unpleasant odours |
1 | 6821-6824 | Rationalised 2023-24
248
Chemistry
Intext Question
Intext Question
Intext Question
Intext Question
Intext Question
8 7
Show how each of the following compounds can be
converted to benzoic acid (i)
Ethylbenzene
(ii)
Acetophenone
(iii)
Bromobenzene
(iv)
Phenylethene (Styrene)
Solution
Solution
Solution
Solution
Solution
(i)
(ii)
(iii)
(iv)
(v)
(vi)
Rationalised 2023-24
249
Aldehydes, Ketones and Carboxylic Acids
Aliphatic carboxylic acids upto nine carbon atoms are colourless
liquids at room temperature with unpleasant odours The higher
acids are wax like solids and are practically odourless due
to their low volatility |
1 | 6822-6825 | 7
Show how each of the following compounds can be
converted to benzoic acid (i)
Ethylbenzene
(ii)
Acetophenone
(iii)
Bromobenzene
(iv)
Phenylethene (Styrene)
Solution
Solution
Solution
Solution
Solution
(i)
(ii)
(iii)
(iv)
(v)
(vi)
Rationalised 2023-24
249
Aldehydes, Ketones and Carboxylic Acids
Aliphatic carboxylic acids upto nine carbon atoms are colourless
liquids at room temperature with unpleasant odours The higher
acids are wax like solids and are practically odourless due
to their low volatility Carboxylic acids are higher boiling
liquids than aldehydes, ketones and even alcohols of
comparable molecular masses |
1 | 6823-6826 | (i)
Ethylbenzene
(ii)
Acetophenone
(iii)
Bromobenzene
(iv)
Phenylethene (Styrene)
Solution
Solution
Solution
Solution
Solution
(i)
(ii)
(iii)
(iv)
(v)
(vi)
Rationalised 2023-24
249
Aldehydes, Ketones and Carboxylic Acids
Aliphatic carboxylic acids upto nine carbon atoms are colourless
liquids at room temperature with unpleasant odours The higher
acids are wax like solids and are practically odourless due
to their low volatility Carboxylic acids are higher boiling
liquids than aldehydes, ketones and even alcohols of
comparable molecular masses This is due to more extensive
association of carboxylic acid molecules through
intermolecular hydrogen bonding |
1 | 6824-6827 | The higher
acids are wax like solids and are practically odourless due
to their low volatility Carboxylic acids are higher boiling
liquids than aldehydes, ketones and even alcohols of
comparable molecular masses This is due to more extensive
association of carboxylic acid molecules through
intermolecular hydrogen bonding The hydrogen bonds are
not broken completely even in the vapour phase |
1 | 6825-6828 | Carboxylic acids are higher boiling
liquids than aldehydes, ketones and even alcohols of
comparable molecular masses This is due to more extensive
association of carboxylic acid molecules through
intermolecular hydrogen bonding The hydrogen bonds are
not broken completely even in the vapour phase In fact,
most carboxylic acids exist as dimer in the vapour phase
or in the aprotic solvents |
1 | 6826-6829 | This is due to more extensive
association of carboxylic acid molecules through
intermolecular hydrogen bonding The hydrogen bonds are
not broken completely even in the vapour phase In fact,
most carboxylic acids exist as dimer in the vapour phase
or in the aprotic solvents Simple aliphatic carboxylic acids having upto four
carbon atoms are miscible in water due to the formation
of hydrogen bonds with water |
1 | 6827-6830 | The hydrogen bonds are
not broken completely even in the vapour phase In fact,
most carboxylic acids exist as dimer in the vapour phase
or in the aprotic solvents Simple aliphatic carboxylic acids having upto four
carbon atoms are miscible in water due to the formation
of hydrogen bonds with water The solubility decreases
with increasing number of carbon atoms |
1 | 6828-6831 | In fact,
most carboxylic acids exist as dimer in the vapour phase
or in the aprotic solvents Simple aliphatic carboxylic acids having upto four
carbon atoms are miscible in water due to the formation
of hydrogen bonds with water The solubility decreases
with increasing number of carbon atoms Higher
carboxylic acids are practically insoluble in water due to
the increased hydrophobic interaction of hydrocarbon
part |
1 | 6829-6832 | Simple aliphatic carboxylic acids having upto four
carbon atoms are miscible in water due to the formation
of hydrogen bonds with water The solubility decreases
with increasing number of carbon atoms Higher
carboxylic acids are practically insoluble in water due to
the increased hydrophobic interaction of hydrocarbon
part Benzoic acid, the simplest aromatic carboxylic acid
is nearly insoluble in cold water |
1 | 6830-6833 | The solubility decreases
with increasing number of carbon atoms Higher
carboxylic acids are practically insoluble in water due to
the increased hydrophobic interaction of hydrocarbon
part Benzoic acid, the simplest aromatic carboxylic acid
is nearly insoluble in cold water Carboxylic acids are
also soluble in less polar organic solvents like benzene,
ether, alcohol, chloroform, etc |
1 | 6831-6834 | Higher
carboxylic acids are practically insoluble in water due to
the increased hydrophobic interaction of hydrocarbon
part Benzoic acid, the simplest aromatic carboxylic acid
is nearly insoluble in cold water Carboxylic acids are
also soluble in less polar organic solvents like benzene,
ether, alcohol, chloroform, etc The reaction of carboxylic acids are classified as follows:
Acidity
Reactions with metals and alkalies
The carboxylic acids like alcohols evolve hydrogen with electropositive
metals and form salts with alkalies similar to phenols |
1 | 6832-6835 | Benzoic acid, the simplest aromatic carboxylic acid
is nearly insoluble in cold water Carboxylic acids are
also soluble in less polar organic solvents like benzene,
ether, alcohol, chloroform, etc The reaction of carboxylic acids are classified as follows:
Acidity
Reactions with metals and alkalies
The carboxylic acids like alcohols evolve hydrogen with electropositive
metals and form salts with alkalies similar to phenols However, unlike
phenols they react with weaker bases such as carbonates and
hydrogencarbonates to evolve carbon dioxide |
1 | 6833-6836 | Carboxylic acids are
also soluble in less polar organic solvents like benzene,
ether, alcohol, chloroform, etc The reaction of carboxylic acids are classified as follows:
Acidity
Reactions with metals and alkalies
The carboxylic acids like alcohols evolve hydrogen with electropositive
metals and form salts with alkalies similar to phenols However, unlike
phenols they react with weaker bases such as carbonates and
hydrogencarbonates to evolve carbon dioxide This reaction is used to
detect the presence of carboxyl group in an organic compound |
1 | 6834-6837 | The reaction of carboxylic acids are classified as follows:
Acidity
Reactions with metals and alkalies
The carboxylic acids like alcohols evolve hydrogen with electropositive
metals and form salts with alkalies similar to phenols However, unlike
phenols they react with weaker bases such as carbonates and
hydrogencarbonates to evolve carbon dioxide This reaction is used to
detect the presence of carboxyl group in an organic compound Carboxylic acids dissociate in water to give resonance stabilised
carboxylate anions and hydronium ion |
1 | 6835-6838 | However, unlike
phenols they react with weaker bases such as carbonates and
hydrogencarbonates to evolve carbon dioxide This reaction is used to
detect the presence of carboxyl group in an organic compound Carboxylic acids dissociate in water to give resonance stabilised
carboxylate anions and hydronium ion 8 |
1 | 6836-6839 | This reaction is used to
detect the presence of carboxyl group in an organic compound Carboxylic acids dissociate in water to give resonance stabilised
carboxylate anions and hydronium ion 8 9 |
1 | 6837-6840 | Carboxylic acids dissociate in water to give resonance stabilised
carboxylate anions and hydronium ion 8 9 1
Reactions
Involving
Cleavage of
O–H Bond
8 |
1 | 6838-6841 | 8 9 1
Reactions
Involving
Cleavage of
O–H Bond
8 8
8 |
1 | 6839-6842 | 9 1
Reactions
Involving
Cleavage of
O–H Bond
8 8
8 8
8 |
1 | 6840-6843 | 1
Reactions
Involving
Cleavage of
O–H Bond
8 8
8 8
8 8
8 |
1 | 6841-6844 | 8
8 8
8 8
8 8
8 |
1 | 6842-6845 | 8
8 8
8 8
8 8 Physical
Physical
Physical
Physical
Physical
Properties
Properties
Properties
Properties
Properties
8 |
1 | 6843-6846 | 8
8 8
8 8 Physical
Physical
Physical
Physical
Physical
Properties
Properties
Properties
Properties
Properties
8 9
8 |
1 | 6844-6847 | 8
8 8 Physical
Physical
Physical
Physical
Physical
Properties
Properties
Properties
Properties
Properties
8 9
8 9
8 |
1 | 6845-6848 | 8 Physical
Physical
Physical
Physical
Physical
Properties
Properties
Properties
Properties
Properties
8 9
8 9
8 9
8 |
1 | 6846-6849 | 9
8 9
8 9
8 9
8 |
1 | 6847-6850 | 9
8 9
8 9
8 9 Chemical Reactions
Chemical Reactions
Chemical Reactions
Chemical Reactions
Chemical Reactions
In vapour state or in
aprotic solvent
Hydrogen bonding of
RCOOH with H2O
Rationalised 2023-24
250
Chemistry
where Keq, is equilibrium constant and Ka is the acid dissociation
constant |
1 | 6848-6851 | 9
8 9
8 9 Chemical Reactions
Chemical Reactions
Chemical Reactions
Chemical Reactions
Chemical Reactions
In vapour state or in
aprotic solvent
Hydrogen bonding of
RCOOH with H2O
Rationalised 2023-24
250
Chemistry
where Keq, is equilibrium constant and Ka is the acid dissociation
constant For convenience, the strength of an acid is generally indicated by
its pKa value rather than its Ka value |
1 | 6849-6852 | 9
8 9 Chemical Reactions
Chemical Reactions
Chemical Reactions
Chemical Reactions
Chemical Reactions
In vapour state or in
aprotic solvent
Hydrogen bonding of
RCOOH with H2O
Rationalised 2023-24
250
Chemistry
where Keq, is equilibrium constant and Ka is the acid dissociation
constant For convenience, the strength of an acid is generally indicated by
its pKa value rather than its Ka value pKa = – log Ka
The pKa of hydrochloric acid is –7 |
1 | 6850-6853 | 9 Chemical Reactions
Chemical Reactions
Chemical Reactions
Chemical Reactions
Chemical Reactions
In vapour state or in
aprotic solvent
Hydrogen bonding of
RCOOH with H2O
Rationalised 2023-24
250
Chemistry
where Keq, is equilibrium constant and Ka is the acid dissociation
constant For convenience, the strength of an acid is generally indicated by
its pKa value rather than its Ka value pKa = – log Ka
The pKa of hydrochloric acid is –7 0, where as pKa of trifluoroacetic
acid (the strongest carboxylic acid), benzoic acid and acetic acid are
0 |
1 | 6851-6854 | For convenience, the strength of an acid is generally indicated by
its pKa value rather than its Ka value pKa = – log Ka
The pKa of hydrochloric acid is –7 0, where as pKa of trifluoroacetic
acid (the strongest carboxylic acid), benzoic acid and acetic acid are
0 23, 4 |
1 | 6852-6855 | pKa = – log Ka
The pKa of hydrochloric acid is –7 0, where as pKa of trifluoroacetic
acid (the strongest carboxylic acid), benzoic acid and acetic acid are
0 23, 4 19 and 4 |
1 | 6853-6856 | 0, where as pKa of trifluoroacetic
acid (the strongest carboxylic acid), benzoic acid and acetic acid are
0 23, 4 19 and 4 76, respectively |
1 | 6854-6857 | 23, 4 19 and 4 76, respectively Smaller the pKa, the stronger the acid ( the better it is as a proton
donor) |
1 | 6855-6858 | 19 and 4 76, respectively Smaller the pKa, the stronger the acid ( the better it is as a proton
donor) Strong acids have pKa values < 1, the acids with pKa values
between 1 and 5 are considered to be moderately strong acids, weak
acids have pKa values between 5 and 15, and extremely weak acids
have pKa values >15 |
1 | 6856-6859 | 76, respectively Smaller the pKa, the stronger the acid ( the better it is as a proton
donor) Strong acids have pKa values < 1, the acids with pKa values
between 1 and 5 are considered to be moderately strong acids, weak
acids have pKa values between 5 and 15, and extremely weak acids
have pKa values >15 Carboxylic acids are weaker than mineral acids, but they are stronger
acids than alcohols and many simple phenols (pKa is ~16 for ethanol
and 10 for phenol) |
1 | 6857-6860 | Smaller the pKa, the stronger the acid ( the better it is as a proton
donor) Strong acids have pKa values < 1, the acids with pKa values
between 1 and 5 are considered to be moderately strong acids, weak
acids have pKa values between 5 and 15, and extremely weak acids
have pKa values >15 Carboxylic acids are weaker than mineral acids, but they are stronger
acids than alcohols and many simple phenols (pKa is ~16 for ethanol
and 10 for phenol) In fact, carboxylic acids are amongst the most acidic
organic compounds you have studied so far |
1 | 6858-6861 | Strong acids have pKa values < 1, the acids with pKa values
between 1 and 5 are considered to be moderately strong acids, weak
acids have pKa values between 5 and 15, and extremely weak acids
have pKa values >15 Carboxylic acids are weaker than mineral acids, but they are stronger
acids than alcohols and many simple phenols (pKa is ~16 for ethanol
and 10 for phenol) In fact, carboxylic acids are amongst the most acidic
organic compounds you have studied so far You already know why
phenols are more acidic than alcohols |
1 | 6859-6862 | Carboxylic acids are weaker than mineral acids, but they are stronger
acids than alcohols and many simple phenols (pKa is ~16 for ethanol
and 10 for phenol) In fact, carboxylic acids are amongst the most acidic
organic compounds you have studied so far You already know why
phenols are more acidic than alcohols The higher acidity of carboxylic
acids as compared to phenols can be understood similarly |
1 | 6860-6863 | In fact, carboxylic acids are amongst the most acidic
organic compounds you have studied so far You already know why
phenols are more acidic than alcohols The higher acidity of carboxylic
acids as compared to phenols can be understood similarly The conjugate
base of carboxylic acid, a carboxylate ion, is stabilised by two equivalent
resonance structures in which the negative charge is at the more
electronegative oxygen atom |
1 | 6861-6864 | You already know why
phenols are more acidic than alcohols The higher acidity of carboxylic
acids as compared to phenols can be understood similarly The conjugate
base of carboxylic acid, a carboxylate ion, is stabilised by two equivalent
resonance structures in which the negative charge is at the more
electronegative oxygen atom The conjugate base of phenol, a phenoxide
ion, has non-equivalent resonance structures in which the negative charge
is at the less electronegative carbon atom |
1 | 6862-6865 | The higher acidity of carboxylic
acids as compared to phenols can be understood similarly The conjugate
base of carboxylic acid, a carboxylate ion, is stabilised by two equivalent
resonance structures in which the negative charge is at the more
electronegative oxygen atom The conjugate base of phenol, a phenoxide
ion, has non-equivalent resonance structures in which the negative charge
is at the less electronegative carbon atom Therefore, resonance in
phenoxide ion is not as important as it is in carboxylate ion |
1 | 6863-6866 | The conjugate
base of carboxylic acid, a carboxylate ion, is stabilised by two equivalent
resonance structures in which the negative charge is at the more
electronegative oxygen atom The conjugate base of phenol, a phenoxide
ion, has non-equivalent resonance structures in which the negative charge
is at the less electronegative carbon atom Therefore, resonance in
phenoxide ion is not as important as it is in carboxylate ion Further, the
negative charge is delocalised over two electronegative oxygen atoms in
carboxylate ion whereas it is less effectively delocalised over one oxygen
atom and less electronegative carbon atoms in phenoxide ion (Unit 7,
Class XII) |
1 | 6864-6867 | The conjugate base of phenol, a phenoxide
ion, has non-equivalent resonance structures in which the negative charge
is at the less electronegative carbon atom Therefore, resonance in
phenoxide ion is not as important as it is in carboxylate ion Further, the
negative charge is delocalised over two electronegative oxygen atoms in
carboxylate ion whereas it is less effectively delocalised over one oxygen
atom and less electronegative carbon atoms in phenoxide ion (Unit 7,
Class XII) Thus, the carboxylate ion is more stabilised than phenoxide
ion, so carboxylic acids are more acidic than phenols |
1 | 6865-6868 | Therefore, resonance in
phenoxide ion is not as important as it is in carboxylate ion Further, the
negative charge is delocalised over two electronegative oxygen atoms in
carboxylate ion whereas it is less effectively delocalised over one oxygen
atom and less electronegative carbon atoms in phenoxide ion (Unit 7,
Class XII) Thus, the carboxylate ion is more stabilised than phenoxide
ion, so carboxylic acids are more acidic than phenols Effect of substituents on the acidity of carboxylic acids:
Substituents may affect the stability of the conjugate base and thus,
also affect the acidity of the carboxylic acids |
1 | 6866-6869 | Further, the
negative charge is delocalised over two electronegative oxygen atoms in
carboxylate ion whereas it is less effectively delocalised over one oxygen
atom and less electronegative carbon atoms in phenoxide ion (Unit 7,
Class XII) Thus, the carboxylate ion is more stabilised than phenoxide
ion, so carboxylic acids are more acidic than phenols Effect of substituents on the acidity of carboxylic acids:
Substituents may affect the stability of the conjugate base and thus,
also affect the acidity of the carboxylic acids Electron withdrawing
groups increase the acidity of carboxylic acids by stabilising the
conjugate base through delocalisation of the negative charge by
inductive and/or resonance effects |
1 | 6867-6870 | Thus, the carboxylate ion is more stabilised than phenoxide
ion, so carboxylic acids are more acidic than phenols Effect of substituents on the acidity of carboxylic acids:
Substituents may affect the stability of the conjugate base and thus,
also affect the acidity of the carboxylic acids Electron withdrawing
groups increase the acidity of carboxylic acids by stabilising the
conjugate base through delocalisation of the negative charge by
inductive and/or resonance effects Conversely, electron donating groups
decrease the acidity by destabilising the conjugate base |
1 | 6868-6871 | Effect of substituents on the acidity of carboxylic acids:
Substituents may affect the stability of the conjugate base and thus,
also affect the acidity of the carboxylic acids Electron withdrawing
groups increase the acidity of carboxylic acids by stabilising the
conjugate base through delocalisation of the negative charge by
inductive and/or resonance effects Conversely, electron donating groups
decrease the acidity by destabilising the conjugate base Electron withdrawing group (EWG)
stabilises the carboxylate anion
and strengthens the acid
Electron donating group (EDG)
destabilises the carboxylate
anion and weakens the acid
For the above reaction:
Rationalised 2023-24
251
Aldehydes, Ketones and Carboxylic Acids
The effect of the following groups in increasing acidity order is
Ph < I < Br < Cl < F < CN < NO2 < CF3
Thus, the following acids are arranged in order of increasing acidity
(based on pKa values):
CF3COOH > CCl3COOH > CHCl2COOH > NO2CH2COOH > NC-CH2COOH >
FCH2COOH > ClCH2COOH > BrCH2COOH > HCOOH > ClCH2CH2COOH >
(continue)
C6H5COOH > C6H5CH2COOH > CH3COOH > CH3CH2COOH
(continue )
Direct attachment of groups such as phenyl or vinyl to the carboxylic
acid, increases the acidity of corresponding carboxylic acid, contrary to
the decrease expected due to resonance effect shown below:
This is because of greater electronegativity of sp
2 hybridised carbon
to which carboxyl carbon is attached |
1 | 6869-6872 | Electron withdrawing
groups increase the acidity of carboxylic acids by stabilising the
conjugate base through delocalisation of the negative charge by
inductive and/or resonance effects Conversely, electron donating groups
decrease the acidity by destabilising the conjugate base Electron withdrawing group (EWG)
stabilises the carboxylate anion
and strengthens the acid
Electron donating group (EDG)
destabilises the carboxylate
anion and weakens the acid
For the above reaction:
Rationalised 2023-24
251
Aldehydes, Ketones and Carboxylic Acids
The effect of the following groups in increasing acidity order is
Ph < I < Br < Cl < F < CN < NO2 < CF3
Thus, the following acids are arranged in order of increasing acidity
(based on pKa values):
CF3COOH > CCl3COOH > CHCl2COOH > NO2CH2COOH > NC-CH2COOH >
FCH2COOH > ClCH2COOH > BrCH2COOH > HCOOH > ClCH2CH2COOH >
(continue)
C6H5COOH > C6H5CH2COOH > CH3COOH > CH3CH2COOH
(continue )
Direct attachment of groups such as phenyl or vinyl to the carboxylic
acid, increases the acidity of corresponding carboxylic acid, contrary to
the decrease expected due to resonance effect shown below:
This is because of greater electronegativity of sp
2 hybridised carbon
to which carboxyl carbon is attached The presence of electron
withdrawing group on the phenyl of aromatic carboxylic acid increases
their acidity while electron donating groups decrease their acidity |
1 | 6870-6873 | Conversely, electron donating groups
decrease the acidity by destabilising the conjugate base Electron withdrawing group (EWG)
stabilises the carboxylate anion
and strengthens the acid
Electron donating group (EDG)
destabilises the carboxylate
anion and weakens the acid
For the above reaction:
Rationalised 2023-24
251
Aldehydes, Ketones and Carboxylic Acids
The effect of the following groups in increasing acidity order is
Ph < I < Br < Cl < F < CN < NO2 < CF3
Thus, the following acids are arranged in order of increasing acidity
(based on pKa values):
CF3COOH > CCl3COOH > CHCl2COOH > NO2CH2COOH > NC-CH2COOH >
FCH2COOH > ClCH2COOH > BrCH2COOH > HCOOH > ClCH2CH2COOH >
(continue)
C6H5COOH > C6H5CH2COOH > CH3COOH > CH3CH2COOH
(continue )
Direct attachment of groups such as phenyl or vinyl to the carboxylic
acid, increases the acidity of corresponding carboxylic acid, contrary to
the decrease expected due to resonance effect shown below:
This is because of greater electronegativity of sp
2 hybridised carbon
to which carboxyl carbon is attached The presence of electron
withdrawing group on the phenyl of aromatic carboxylic acid increases
their acidity while electron donating groups decrease their acidity COOH
OCH3
COOH
COOH
NO2
4-Methoxy
benzoic acid
(p
= 4 |
1 | 6871-6874 | Electron withdrawing group (EWG)
stabilises the carboxylate anion
and strengthens the acid
Electron donating group (EDG)
destabilises the carboxylate
anion and weakens the acid
For the above reaction:
Rationalised 2023-24
251
Aldehydes, Ketones and Carboxylic Acids
The effect of the following groups in increasing acidity order is
Ph < I < Br < Cl < F < CN < NO2 < CF3
Thus, the following acids are arranged in order of increasing acidity
(based on pKa values):
CF3COOH > CCl3COOH > CHCl2COOH > NO2CH2COOH > NC-CH2COOH >
FCH2COOH > ClCH2COOH > BrCH2COOH > HCOOH > ClCH2CH2COOH >
(continue)
C6H5COOH > C6H5CH2COOH > CH3COOH > CH3CH2COOH
(continue )
Direct attachment of groups such as phenyl or vinyl to the carboxylic
acid, increases the acidity of corresponding carboxylic acid, contrary to
the decrease expected due to resonance effect shown below:
This is because of greater electronegativity of sp
2 hybridised carbon
to which carboxyl carbon is attached The presence of electron
withdrawing group on the phenyl of aromatic carboxylic acid increases
their acidity while electron donating groups decrease their acidity COOH
OCH3
COOH
COOH
NO2
4-Methoxy
benzoic acid
(p
= 4 46)
Ka
Benzoic acid
(p
= 4 |
1 | 6872-6875 | The presence of electron
withdrawing group on the phenyl of aromatic carboxylic acid increases
their acidity while electron donating groups decrease their acidity COOH
OCH3
COOH
COOH
NO2
4-Methoxy
benzoic acid
(p
= 4 46)
Ka
Benzoic acid
(p
= 4 19)
Ka
4-Nitrobenzoic
acid
(p
= 3 |
1 | 6873-6876 | COOH
OCH3
COOH
COOH
NO2
4-Methoxy
benzoic acid
(p
= 4 46)
Ka
Benzoic acid
(p
= 4 19)
Ka
4-Nitrobenzoic
acid
(p
= 3 41)
Ka
1 |
1 | 6874-6877 | 46)
Ka
Benzoic acid
(p
= 4 19)
Ka
4-Nitrobenzoic
acid
(p
= 3 41)
Ka
1 Formation of anhydride
Carboxylic acids on heating with mineral acids such as H2SO4 or with
P2O5 give corresponding anhydride |
1 | 6875-6878 | 19)
Ka
4-Nitrobenzoic
acid
(p
= 3 41)
Ka
1 Formation of anhydride
Carboxylic acids on heating with mineral acids such as H2SO4 or with
P2O5 give corresponding anhydride 2 |
1 | 6876-6879 | 41)
Ka
1 Formation of anhydride
Carboxylic acids on heating with mineral acids such as H2SO4 or with
P2O5 give corresponding anhydride 2 Esterification
Carboxylic acids are esterified with alcohols or phenols in the presence
of a mineral acid such as concentrated H2SO4 or HCl gas as a catalyst |
1 | 6877-6880 | Formation of anhydride
Carboxylic acids on heating with mineral acids such as H2SO4 or with
P2O5 give corresponding anhydride 2 Esterification
Carboxylic acids are esterified with alcohols or phenols in the presence
of a mineral acid such as concentrated H2SO4 or HCl gas as a catalyst 8 |
1 | 6878-6881 | 2 Esterification
Carboxylic acids are esterified with alcohols or phenols in the presence
of a mineral acid such as concentrated H2SO4 or HCl gas as a catalyst 8 9 |
1 | 6879-6882 | Esterification
Carboxylic acids are esterified with alcohols or phenols in the presence
of a mineral acid such as concentrated H2SO4 or HCl gas as a catalyst 8 9 2
Reactions
Involving
Cleavage of
C–OH Bond
Rationalised 2023-24
252
Chemistry
Mechanism of esterification of carboxylic acids: The esterification of carboxylic
acids with alcohols is a kind of nucleophilic acyl substitution |
1 | 6880-6883 | 8 9 2
Reactions
Involving
Cleavage of
C–OH Bond
Rationalised 2023-24
252
Chemistry
Mechanism of esterification of carboxylic acids: The esterification of carboxylic
acids with alcohols is a kind of nucleophilic acyl substitution Protonation of the
carbonyl oxygen activates the carbonyl group towards nucleophilic addition of the
alcohol |
1 | 6881-6884 | 9 2
Reactions
Involving
Cleavage of
C–OH Bond
Rationalised 2023-24
252
Chemistry
Mechanism of esterification of carboxylic acids: The esterification of carboxylic
acids with alcohols is a kind of nucleophilic acyl substitution Protonation of the
carbonyl oxygen activates the carbonyl group towards nucleophilic addition of the
alcohol Proton transfer in the tetrahedral intermediate converts the hydroxyl group
into –
+OH2 group, which, being a better leaving group, is eliminated as neutral water
molecule |
1 | 6882-6885 | 2
Reactions
Involving
Cleavage of
C–OH Bond
Rationalised 2023-24
252
Chemistry
Mechanism of esterification of carboxylic acids: The esterification of carboxylic
acids with alcohols is a kind of nucleophilic acyl substitution Protonation of the
carbonyl oxygen activates the carbonyl group towards nucleophilic addition of the
alcohol Proton transfer in the tetrahedral intermediate converts the hydroxyl group
into –
+OH2 group, which, being a better leaving group, is eliminated as neutral water
molecule The protonated ester so formed finally loses a proton to give the ester |
1 | 6883-6886 | Protonation of the
carbonyl oxygen activates the carbonyl group towards nucleophilic addition of the
alcohol Proton transfer in the tetrahedral intermediate converts the hydroxyl group
into –
+OH2 group, which, being a better leaving group, is eliminated as neutral water
molecule The protonated ester so formed finally loses a proton to give the ester 3 |
1 | 6884-6887 | Proton transfer in the tetrahedral intermediate converts the hydroxyl group
into –
+OH2 group, which, being a better leaving group, is eliminated as neutral water
molecule The protonated ester so formed finally loses a proton to give the ester 3 Reactions with PCl5, PCl3 and SOCl2
The hydroxyl group of carboxylic acids, behaves like that of alcohols
and is easily replaced by chlorine atom on treating with PCl5, PCl3 or
SOCl2 |
1 | 6885-6888 | The protonated ester so formed finally loses a proton to give the ester 3 Reactions with PCl5, PCl3 and SOCl2
The hydroxyl group of carboxylic acids, behaves like that of alcohols
and is easily replaced by chlorine atom on treating with PCl5, PCl3 or
SOCl2 Thionyl chloride (SOCl2) is preferred because the other two
products are gaseous and escape the reaction mixture making the
purification of the products easier |
1 | 6886-6889 | 3 Reactions with PCl5, PCl3 and SOCl2
The hydroxyl group of carboxylic acids, behaves like that of alcohols
and is easily replaced by chlorine atom on treating with PCl5, PCl3 or
SOCl2 Thionyl chloride (SOCl2) is preferred because the other two
products are gaseous and escape the reaction mixture making the
purification of the products easier 4 |
1 | 6887-6890 | Reactions with PCl5, PCl3 and SOCl2
The hydroxyl group of carboxylic acids, behaves like that of alcohols
and is easily replaced by chlorine atom on treating with PCl5, PCl3 or
SOCl2 Thionyl chloride (SOCl2) is preferred because the other two
products are gaseous and escape the reaction mixture making the
purification of the products easier 4 Reaction with ammonia
Carboxylic acids react with ammonia to give ammonium salt which
on further heating at high temperature give amides |
1 | 6888-6891 | Thionyl chloride (SOCl2) is preferred because the other two
products are gaseous and escape the reaction mixture making the
purification of the products easier 4 Reaction with ammonia
Carboxylic acids react with ammonia to give ammonium salt which
on further heating at high temperature give amides For example:
Rationalised 2023-24
253
Aldehydes, Ketones and Carboxylic Acids
8 |
1 | 6889-6892 | 4 Reaction with ammonia
Carboxylic acids react with ammonia to give ammonium salt which
on further heating at high temperature give amides For example:
Rationalised 2023-24
253
Aldehydes, Ketones and Carboxylic Acids
8 9 |
1 | 6890-6893 | Reaction with ammonia
Carboxylic acids react with ammonia to give ammonium salt which
on further heating at high temperature give amides For example:
Rationalised 2023-24
253
Aldehydes, Ketones and Carboxylic Acids
8 9 3
Reactions
Involving
–COOH
Group
1 |
1 | 6891-6894 | For example:
Rationalised 2023-24
253
Aldehydes, Ketones and Carboxylic Acids
8 9 3
Reactions
Involving
–COOH
Group
1 Reduction
Carboxylic acids are reduced to primary alcohols by lithium
aluminium hydride or better with diborane |
1 | 6892-6895 | 9 3
Reactions
Involving
–COOH
Group
1 Reduction
Carboxylic acids are reduced to primary alcohols by lithium
aluminium hydride or better with diborane Diborane does not easily
reduce functional groups such as ester, nitro, halo, etc |
1 | 6893-6896 | 3
Reactions
Involving
–COOH
Group
1 Reduction
Carboxylic acids are reduced to primary alcohols by lithium
aluminium hydride or better with diborane Diborane does not easily
reduce functional groups such as ester, nitro, halo, etc Sodium
borohydride does not reduce the carboxyl group |
1 | 6894-6897 | Reduction
Carboxylic acids are reduced to primary alcohols by lithium
aluminium hydride or better with diborane Diborane does not easily
reduce functional groups such as ester, nitro, halo, etc Sodium
borohydride does not reduce the carboxyl group 2 |
1 | 6895-6898 | Diborane does not easily
reduce functional groups such as ester, nitro, halo, etc Sodium
borohydride does not reduce the carboxyl group 2 Decarboxylation
Carboxylic acids lose carbon dioxide to form hydrocarbons when their
sodium salts are heated with sodalime (NaOH and CaO in the ratio of
3 : 1) |
1 | 6896-6899 | Sodium
borohydride does not reduce the carboxyl group 2 Decarboxylation
Carboxylic acids lose carbon dioxide to form hydrocarbons when their
sodium salts are heated with sodalime (NaOH and CaO in the ratio of
3 : 1) The reaction is known as decarboxylation |
1 | 6897-6900 | 2 Decarboxylation
Carboxylic acids lose carbon dioxide to form hydrocarbons when their
sodium salts are heated with sodalime (NaOH and CaO in the ratio of
3 : 1) The reaction is known as decarboxylation Alkali metal salts of carboxylic acids also undergo decarboxylation
on electrolysis of their aqueous solutions and form hydrocarbons having
twice the number of carbon atoms present in the alkyl group of the acid |
1 | 6898-6901 | Decarboxylation
Carboxylic acids lose carbon dioxide to form hydrocarbons when their
sodium salts are heated with sodalime (NaOH and CaO in the ratio of
3 : 1) The reaction is known as decarboxylation Alkali metal salts of carboxylic acids also undergo decarboxylation
on electrolysis of their aqueous solutions and form hydrocarbons having
twice the number of carbon atoms present in the alkyl group of the acid The reaction is known as Kolbe electrolysis (Unit 9, Class XI) |
1 | 6899-6902 | The reaction is known as decarboxylation Alkali metal salts of carboxylic acids also undergo decarboxylation
on electrolysis of their aqueous solutions and form hydrocarbons having
twice the number of carbon atoms present in the alkyl group of the acid The reaction is known as Kolbe electrolysis (Unit 9, Class XI) 1 |
1 | 6900-6903 | Alkali metal salts of carboxylic acids also undergo decarboxylation
on electrolysis of their aqueous solutions and form hydrocarbons having
twice the number of carbon atoms present in the alkyl group of the acid The reaction is known as Kolbe electrolysis (Unit 9, Class XI) 1 Halogenation
Carboxylic acids having an a-hydrogen are halogenated at the
a-position on treatment with chlorine or bromine in the presence of
small amount of red phosphorus to give a-halocarboxylic acids |
1 | 6901-6904 | The reaction is known as Kolbe electrolysis (Unit 9, Class XI) 1 Halogenation
Carboxylic acids having an a-hydrogen are halogenated at the
a-position on treatment with chlorine or bromine in the presence of
small amount of red phosphorus to give a-halocarboxylic acids The
reaction is known as Hell-Volhard-Zelinsky reaction |
1 | 6902-6905 | 1 Halogenation
Carboxylic acids having an a-hydrogen are halogenated at the
a-position on treatment with chlorine or bromine in the presence of
small amount of red phosphorus to give a-halocarboxylic acids The
reaction is known as Hell-Volhard-Zelinsky reaction 8 |
1 | 6903-6906 | Halogenation
Carboxylic acids having an a-hydrogen are halogenated at the
a-position on treatment with chlorine or bromine in the presence of
small amount of red phosphorus to give a-halocarboxylic acids The
reaction is known as Hell-Volhard-Zelinsky reaction 8 9 |
1 | 6904-6907 | The
reaction is known as Hell-Volhard-Zelinsky reaction 8 9 4 Substitution
Reactions in the
Hydrocarbon Part
Rationalised 2023-24
254
Chemistry
8 |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.