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1 | 6605-6608 | The following compounds of molecular masses 58
and 60 are ranked in order of increasing boiling points b p (K)
Molecular Mass
n-Butane
273
58
Methoxyethane
281
60
Propanal
322
58
Acetone
329
58
Propan-1-ol
370
60
The lower members of aldehydes and ketones such as methanal,
ethanal and propanone are miscible with water in all proportions,
because they form hydrogen bond with water |
1 | 6606-6609 | b p (K)
Molecular Mass
n-Butane
273
58
Methoxyethane
281
60
Propanal
322
58
Acetone
329
58
Propan-1-ol
370
60
The lower members of aldehydes and ketones such as methanal,
ethanal and propanone are miscible with water in all proportions,
because they form hydrogen bond with water However, the solubility of aldehydes and ketones decreases rapidly
on increasing the length of alkyl chain |
1 | 6607-6610 | p (K)
Molecular Mass
n-Butane
273
58
Methoxyethane
281
60
Propanal
322
58
Acetone
329
58
Propan-1-ol
370
60
The lower members of aldehydes and ketones such as methanal,
ethanal and propanone are miscible with water in all proportions,
because they form hydrogen bond with water However, the solubility of aldehydes and ketones decreases rapidly
on increasing the length of alkyl chain All aldehydes and ketones are
fairly soluble in organic solvents like benzene, ether, methanol,
chloroform, etc |
1 | 6608-6611 | (K)
Molecular Mass
n-Butane
273
58
Methoxyethane
281
60
Propanal
322
58
Acetone
329
58
Propan-1-ol
370
60
The lower members of aldehydes and ketones such as methanal,
ethanal and propanone are miscible with water in all proportions,
because they form hydrogen bond with water However, the solubility of aldehydes and ketones decreases rapidly
on increasing the length of alkyl chain All aldehydes and ketones are
fairly soluble in organic solvents like benzene, ether, methanol,
chloroform, etc The lower aldehydes have sharp pungent odours |
1 | 6609-6612 | However, the solubility of aldehydes and ketones decreases rapidly
on increasing the length of alkyl chain All aldehydes and ketones are
fairly soluble in organic solvents like benzene, ether, methanol,
chloroform, etc The lower aldehydes have sharp pungent odours As
the size of the molecule increases, the odour becomes less pungent
and more fragrant |
1 | 6610-6613 | All aldehydes and ketones are
fairly soluble in organic solvents like benzene, ether, methanol,
chloroform, etc The lower aldehydes have sharp pungent odours As
the size of the molecule increases, the odour becomes less pungent
and more fragrant In fact, many naturally occurring aldehydes and
ketones are used in the blending of perfumes and flavouring agents |
1 | 6611-6614 | The lower aldehydes have sharp pungent odours As
the size of the molecule increases, the odour becomes less pungent
and more fragrant In fact, many naturally occurring aldehydes and
ketones are used in the blending of perfumes and flavouring agents 8 |
1 | 6612-6615 | As
the size of the molecule increases, the odour becomes less pungent
and more fragrant In fact, many naturally occurring aldehydes and
ketones are used in the blending of perfumes and flavouring agents 8 3 Physical
8 |
1 | 6613-6616 | In fact, many naturally occurring aldehydes and
ketones are used in the blending of perfumes and flavouring agents 8 3 Physical
8 3 Physical
8 |
1 | 6614-6617 | 8 3 Physical
8 3 Physical
8 3 Physical
8 |
1 | 6615-6618 | 3 Physical
8 3 Physical
8 3 Physical
8 3 Physical
8 |
1 | 6616-6619 | 3 Physical
8 3 Physical
8 3 Physical
8 3 Physical
Properties
Properties
Properties
Properties
Properties
Arrange the following compounds in the increasing order of their
boiling points:
CH3CH2CH2CHO, CH3CH2CH2CH2OH, H5C2-O-C2H5, CH3CH2CH2CH3
The molecular masses of these compounds are in the range of 72 to
74 |
1 | 6617-6620 | 3 Physical
8 3 Physical
8 3 Physical
Properties
Properties
Properties
Properties
Properties
Arrange the following compounds in the increasing order of their
boiling points:
CH3CH2CH2CHO, CH3CH2CH2CH2OH, H5C2-O-C2H5, CH3CH2CH2CH3
The molecular masses of these compounds are in the range of 72 to
74 Since only butan-1-ol molecules are associated due to extensive
intermolecular hydrogen bonding, therefore, the boiling point of
butan-1-ol would be the highest |
1 | 6618-6621 | 3 Physical
8 3 Physical
Properties
Properties
Properties
Properties
Properties
Arrange the following compounds in the increasing order of their
boiling points:
CH3CH2CH2CHO, CH3CH2CH2CH2OH, H5C2-O-C2H5, CH3CH2CH2CH3
The molecular masses of these compounds are in the range of 72 to
74 Since only butan-1-ol molecules are associated due to extensive
intermolecular hydrogen bonding, therefore, the boiling point of
butan-1-ol would be the highest Butanal is more polar than
ethoxyethane |
1 | 6619-6622 | 3 Physical
Properties
Properties
Properties
Properties
Properties
Arrange the following compounds in the increasing order of their
boiling points:
CH3CH2CH2CHO, CH3CH2CH2CH2OH, H5C2-O-C2H5, CH3CH2CH2CH3
The molecular masses of these compounds are in the range of 72 to
74 Since only butan-1-ol molecules are associated due to extensive
intermolecular hydrogen bonding, therefore, the boiling point of
butan-1-ol would be the highest Butanal is more polar than
ethoxyethane Therefore, the intermolecular dipole-dipole attraction
is stronger in the former |
1 | 6620-6623 | Since only butan-1-ol molecules are associated due to extensive
intermolecular hydrogen bonding, therefore, the boiling point of
butan-1-ol would be the highest Butanal is more polar than
ethoxyethane Therefore, the intermolecular dipole-dipole attraction
is stronger in the former n-Pentane molecules have only weak van
der Waals forces |
1 | 6621-6624 | Butanal is more polar than
ethoxyethane Therefore, the intermolecular dipole-dipole attraction
is stronger in the former n-Pentane molecules have only weak van
der Waals forces Hence increasing order of boiling points of the
given compounds is as follows:
CH3CH2CH2CH3 < H5C2-O-C2H5 < CH3CH2CH2CHO < CH3CH2CH2CH2OH
Example 8 |
1 | 6622-6625 | Therefore, the intermolecular dipole-dipole attraction
is stronger in the former n-Pentane molecules have only weak van
der Waals forces Hence increasing order of boiling points of the
given compounds is as follows:
CH3CH2CH2CH3 < H5C2-O-C2H5 < CH3CH2CH2CHO < CH3CH2CH2CH2OH
Example 8 2
Example 8 |
1 | 6623-6626 | n-Pentane molecules have only weak van
der Waals forces Hence increasing order of boiling points of the
given compounds is as follows:
CH3CH2CH2CH3 < H5C2-O-C2H5 < CH3CH2CH2CHO < CH3CH2CH2CH2OH
Example 8 2
Example 8 2
Example 8 |
1 | 6624-6627 | Hence increasing order of boiling points of the
given compounds is as follows:
CH3CH2CH2CH3 < H5C2-O-C2H5 < CH3CH2CH2CHO < CH3CH2CH2CH2OH
Example 8 2
Example 8 2
Example 8 2
Example 8 |
1 | 6625-6628 | 2
Example 8 2
Example 8 2
Example 8 2
Example 8 |
1 | 6626-6629 | 2
Example 8 2
Example 8 2
Example 8 2
Solution
Solution
Solution
Solution
Solution
Rationalised 2023-24
236
Chemistry
Since aldehydes and ketones both possess the carbonyl functional
group, they undergo similar chemical reactions |
1 | 6627-6630 | 2
Example 8 2
Example 8 2
Solution
Solution
Solution
Solution
Solution
Rationalised 2023-24
236
Chemistry
Since aldehydes and ketones both possess the carbonyl functional
group, they undergo similar chemical reactions 1 |
1 | 6628-6631 | 2
Example 8 2
Solution
Solution
Solution
Solution
Solution
Rationalised 2023-24
236
Chemistry
Since aldehydes and ketones both possess the carbonyl functional
group, they undergo similar chemical reactions 1 Nucleophilic addition reactions
Contrary to electrophilic addition reactions observed in alkenes, the
aldehydes and ketones undergo nucleophilic addition reactions |
1 | 6629-6632 | 2
Solution
Solution
Solution
Solution
Solution
Rationalised 2023-24
236
Chemistry
Since aldehydes and ketones both possess the carbonyl functional
group, they undergo similar chemical reactions 1 Nucleophilic addition reactions
Contrary to electrophilic addition reactions observed in alkenes, the
aldehydes and ketones undergo nucleophilic addition reactions (i) Mechanism of nucleophilic addition reactions
A nucleophile attacks the electrophilic carbon atom of the polar
carbonyl group from a direction approximately perpendicular
to the plane of sp
2 hybridised orbitals of carbonyl carbon (Fig |
1 | 6630-6633 | 1 Nucleophilic addition reactions
Contrary to electrophilic addition reactions observed in alkenes, the
aldehydes and ketones undergo nucleophilic addition reactions (i) Mechanism of nucleophilic addition reactions
A nucleophile attacks the electrophilic carbon atom of the polar
carbonyl group from a direction approximately perpendicular
to the plane of sp
2 hybridised orbitals of carbonyl carbon (Fig 8 |
1 | 6631-6634 | Nucleophilic addition reactions
Contrary to electrophilic addition reactions observed in alkenes, the
aldehydes and ketones undergo nucleophilic addition reactions (i) Mechanism of nucleophilic addition reactions
A nucleophile attacks the electrophilic carbon atom of the polar
carbonyl group from a direction approximately perpendicular
to the plane of sp
2 hybridised orbitals of carbonyl carbon (Fig 8 2) |
1 | 6632-6635 | (i) Mechanism of nucleophilic addition reactions
A nucleophile attacks the electrophilic carbon atom of the polar
carbonyl group from a direction approximately perpendicular
to the plane of sp
2 hybridised orbitals of carbonyl carbon (Fig 8 2) The hybridisation of carbon changes from sp
2 to sp
3 in
this process, and a tetrahedral alkoxide intermediate is
produced |
1 | 6633-6636 | 8 2) The hybridisation of carbon changes from sp
2 to sp
3 in
this process, and a tetrahedral alkoxide intermediate is
produced This intermediate captures a proton from the
reaction medium to give
the electrically neutral
product |
1 | 6634-6637 | 2) The hybridisation of carbon changes from sp
2 to sp
3 in
this process, and a tetrahedral alkoxide intermediate is
produced This intermediate captures a proton from the
reaction medium to give
the electrically neutral
product The net result is
addition of Nu
– and H
+
across the carbon oxygen
double bond as shown in
Fig |
1 | 6635-6638 | The hybridisation of carbon changes from sp
2 to sp
3 in
this process, and a tetrahedral alkoxide intermediate is
produced This intermediate captures a proton from the
reaction medium to give
the electrically neutral
product The net result is
addition of Nu
– and H
+
across the carbon oxygen
double bond as shown in
Fig 8 |
1 | 6636-6639 | This intermediate captures a proton from the
reaction medium to give
the electrically neutral
product The net result is
addition of Nu
– and H
+
across the carbon oxygen
double bond as shown in
Fig 8 2 |
1 | 6637-6640 | The net result is
addition of Nu
– and H
+
across the carbon oxygen
double bond as shown in
Fig 8 2 Intext Question
Intext Question
Intext Question
Intext Question
Intext Question
8 |
1 | 6638-6641 | 8 2 Intext Question
Intext Question
Intext Question
Intext Question
Intext Question
8 3
Arrange the following compounds in increasing order of
their boiling points |
1 | 6639-6642 | 2 Intext Question
Intext Question
Intext Question
Intext Question
Intext Question
8 3
Arrange the following compounds in increasing order of
their boiling points CH3CHO, CH3CH2OH, CH3OCH3, CH3CH2CH3
Fig |
1 | 6640-6643 | Intext Question
Intext Question
Intext Question
Intext Question
Intext Question
8 3
Arrange the following compounds in increasing order of
their boiling points CH3CHO, CH3CH2OH, CH3OCH3, CH3CH2CH3
Fig 8 |
1 | 6641-6644 | 3
Arrange the following compounds in increasing order of
their boiling points CH3CHO, CH3CH2OH, CH3OCH3, CH3CH2CH3
Fig 8 2: Nucleophilic attack on carbonyl carbon
Would you expect benzaldehyde to be more reactive or less reactive in
nucleophilic addition reactions than propanal |
1 | 6642-6645 | CH3CHO, CH3CH2OH, CH3OCH3, CH3CH2CH3
Fig 8 2: Nucleophilic attack on carbonyl carbon
Would you expect benzaldehyde to be more reactive or less reactive in
nucleophilic addition reactions than propanal Explain your answer |
1 | 6643-6646 | 8 2: Nucleophilic attack on carbonyl carbon
Would you expect benzaldehyde to be more reactive or less reactive in
nucleophilic addition reactions than propanal Explain your answer The carbon atom of the carbonyl group of benzaldehyde is less
electrophilic than carbon atom of the carbonyl group present in
propanal |
1 | 6644-6647 | 2: Nucleophilic attack on carbonyl carbon
Would you expect benzaldehyde to be more reactive or less reactive in
nucleophilic addition reactions than propanal Explain your answer The carbon atom of the carbonyl group of benzaldehyde is less
electrophilic than carbon atom of the carbonyl group present in
propanal The polarity of the carbonyl
group is reduced in benzaldehyde due
to resonance as shown below and
hence it is less reactive than propanal |
1 | 6645-6648 | Explain your answer The carbon atom of the carbonyl group of benzaldehyde is less
electrophilic than carbon atom of the carbonyl group present in
propanal The polarity of the carbonyl
group is reduced in benzaldehyde due
to resonance as shown below and
hence it is less reactive than propanal Example 8 |
1 | 6646-6649 | The carbon atom of the carbonyl group of benzaldehyde is less
electrophilic than carbon atom of the carbonyl group present in
propanal The polarity of the carbonyl
group is reduced in benzaldehyde due
to resonance as shown below and
hence it is less reactive than propanal Example 8 3
Example 8 |
1 | 6647-6650 | The polarity of the carbonyl
group is reduced in benzaldehyde due
to resonance as shown below and
hence it is less reactive than propanal Example 8 3
Example 8 3
Example 8 |
1 | 6648-6651 | Example 8 3
Example 8 3
Example 8 3
Example 8 |
1 | 6649-6652 | 3
Example 8 3
Example 8 3
Example 8 3
Example 8 |
1 | 6650-6653 | 3
Example 8 3
Example 8 3
Example 8 3
Solution
Solution
Solution
Solution
Solution
(ii) Reactivity
Aldehydes are generally more reactive than ketones in
nucleophilic addition reactions due to steric and electronic
reasons |
1 | 6651-6654 | 3
Example 8 3
Example 8 3
Solution
Solution
Solution
Solution
Solution
(ii) Reactivity
Aldehydes are generally more reactive than ketones in
nucleophilic addition reactions due to steric and electronic
reasons Sterically, the presence of two relatively large
substituents in ketones hinders the approach of nucleophile to
carbonyl carbon than in aldehydes having only one such
substituent |
1 | 6652-6655 | 3
Example 8 3
Solution
Solution
Solution
Solution
Solution
(ii) Reactivity
Aldehydes are generally more reactive than ketones in
nucleophilic addition reactions due to steric and electronic
reasons Sterically, the presence of two relatively large
substituents in ketones hinders the approach of nucleophile to
carbonyl carbon than in aldehydes having only one such
substituent Electronically, aldehydes are more reactive than
ketones because two alkyl groups reduce the electrophilicity of
the carbonyl carbon more effectively than in former |
1 | 6653-6656 | 3
Solution
Solution
Solution
Solution
Solution
(ii) Reactivity
Aldehydes are generally more reactive than ketones in
nucleophilic addition reactions due to steric and electronic
reasons Sterically, the presence of two relatively large
substituents in ketones hinders the approach of nucleophile to
carbonyl carbon than in aldehydes having only one such
substituent Electronically, aldehydes are more reactive than
ketones because two alkyl groups reduce the electrophilicity of
the carbonyl carbon more effectively than in former 8 |
1 | 6654-6657 | Sterically, the presence of two relatively large
substituents in ketones hinders the approach of nucleophile to
carbonyl carbon than in aldehydes having only one such
substituent Electronically, aldehydes are more reactive than
ketones because two alkyl groups reduce the electrophilicity of
the carbonyl carbon more effectively than in former 8 4 Chemical
8 |
1 | 6655-6658 | Electronically, aldehydes are more reactive than
ketones because two alkyl groups reduce the electrophilicity of
the carbonyl carbon more effectively than in former 8 4 Chemical
8 4 Chemical
8 |
1 | 6656-6659 | 8 4 Chemical
8 4 Chemical
8 4 Chemical
8 |
1 | 6657-6660 | 4 Chemical
8 4 Chemical
8 4 Chemical
8 4 Chemical
8 |
1 | 6658-6661 | 4 Chemical
8 4 Chemical
8 4 Chemical
8 4 Chemical
Reactions
Reactions
Reactions
Reactions
Reactions
Rationalised 2023-24
237
Aldehydes, Ketones and Carboxylic Acids
(iii) Some important examples of nucleophilic addition and
nucleophilic addition-elimination reactions:
(a) Addition of hydrogen cyanide (HCN): Aldehydes
and ketones react with hydrogen cyanide (HCN)
to yield cyanohydrins |
1 | 6659-6662 | 4 Chemical
8 4 Chemical
8 4 Chemical
Reactions
Reactions
Reactions
Reactions
Reactions
Rationalised 2023-24
237
Aldehydes, Ketones and Carboxylic Acids
(iii) Some important examples of nucleophilic addition and
nucleophilic addition-elimination reactions:
(a) Addition of hydrogen cyanide (HCN): Aldehydes
and ketones react with hydrogen cyanide (HCN)
to yield cyanohydrins This reaction occurs very
slowly with pure HCN |
1 | 6660-6663 | 4 Chemical
8 4 Chemical
Reactions
Reactions
Reactions
Reactions
Reactions
Rationalised 2023-24
237
Aldehydes, Ketones and Carboxylic Acids
(iii) Some important examples of nucleophilic addition and
nucleophilic addition-elimination reactions:
(a) Addition of hydrogen cyanide (HCN): Aldehydes
and ketones react with hydrogen cyanide (HCN)
to yield cyanohydrins This reaction occurs very
slowly with pure HCN Therefore, it is catalysed
by a base and the generated cyanide ion (CN
being a stronger nucleophile readily adds to-)
carbonyl compounds to yield corresponding
cyanohydrin |
1 | 6661-6664 | 4 Chemical
Reactions
Reactions
Reactions
Reactions
Reactions
Rationalised 2023-24
237
Aldehydes, Ketones and Carboxylic Acids
(iii) Some important examples of nucleophilic addition and
nucleophilic addition-elimination reactions:
(a) Addition of hydrogen cyanide (HCN): Aldehydes
and ketones react with hydrogen cyanide (HCN)
to yield cyanohydrins This reaction occurs very
slowly with pure HCN Therefore, it is catalysed
by a base and the generated cyanide ion (CN
being a stronger nucleophile readily adds to-)
carbonyl compounds to yield corresponding
cyanohydrin Cyanohydrins
are
useful
synthetic
intermediates |
1 | 6662-6665 | This reaction occurs very
slowly with pure HCN Therefore, it is catalysed
by a base and the generated cyanide ion (CN
being a stronger nucleophile readily adds to-)
carbonyl compounds to yield corresponding
cyanohydrin Cyanohydrins
are
useful
synthetic
intermediates (b) Addition of sodium hydrogensulphite: Sodium
hydrogensulphite adds to aldehydes and
ketones to form the addition products |
1 | 6663-6666 | Therefore, it is catalysed
by a base and the generated cyanide ion (CN
being a stronger nucleophile readily adds to-)
carbonyl compounds to yield corresponding
cyanohydrin Cyanohydrins
are
useful
synthetic
intermediates (b) Addition of sodium hydrogensulphite: Sodium
hydrogensulphite adds to aldehydes and
ketones to form the addition products The position of
the equilibrium
lies largely to
the right hand
side for most
aldehydes and to
the left for most
ketones due to steric reasons |
1 | 6664-6667 | Cyanohydrins
are
useful
synthetic
intermediates (b) Addition of sodium hydrogensulphite: Sodium
hydrogensulphite adds to aldehydes and
ketones to form the addition products The position of
the equilibrium
lies largely to
the right hand
side for most
aldehydes and to
the left for most
ketones due to steric reasons The hydrogensulphite addition
compound is water soluble and can be converted back to the
original carbonyl compound by treating it with dilute mineral
acid or alkali |
1 | 6665-6668 | (b) Addition of sodium hydrogensulphite: Sodium
hydrogensulphite adds to aldehydes and
ketones to form the addition products The position of
the equilibrium
lies largely to
the right hand
side for most
aldehydes and to
the left for most
ketones due to steric reasons The hydrogensulphite addition
compound is water soluble and can be converted back to the
original carbonyl compound by treating it with dilute mineral
acid or alkali Therefore, these are useful for separation and
purification of aldehydes |
1 | 6666-6669 | The position of
the equilibrium
lies largely to
the right hand
side for most
aldehydes and to
the left for most
ketones due to steric reasons The hydrogensulphite addition
compound is water soluble and can be converted back to the
original carbonyl compound by treating it with dilute mineral
acid or alkali Therefore, these are useful for separation and
purification of aldehydes (c) Addition of Grignard reagents: (refer Unit 7, Class XII) |
1 | 6667-6670 | The hydrogensulphite addition
compound is water soluble and can be converted back to the
original carbonyl compound by treating it with dilute mineral
acid or alkali Therefore, these are useful for separation and
purification of aldehydes (c) Addition of Grignard reagents: (refer Unit 7, Class XII) (d) Addition of alcohols: Aldehydes react with one equivalent of
monohydric alcohol in the presence of dry hydrogen chloride
to yield alkoxyalcohol intermediate, known as hemiacetals,
which further react with one more molecule of alcohol to
give a gem-dialkoxy
compound known as
acetal as shown in the
reaction |
1 | 6668-6671 | Therefore, these are useful for separation and
purification of aldehydes (c) Addition of Grignard reagents: (refer Unit 7, Class XII) (d) Addition of alcohols: Aldehydes react with one equivalent of
monohydric alcohol in the presence of dry hydrogen chloride
to yield alkoxyalcohol intermediate, known as hemiacetals,
which further react with one more molecule of alcohol to
give a gem-dialkoxy
compound known as
acetal as shown in the
reaction Ketones react with
ethylene glycol under
similar conditions to form
cyclic products known as
ethylene glycol ketals |
1 | 6669-6672 | (c) Addition of Grignard reagents: (refer Unit 7, Class XII) (d) Addition of alcohols: Aldehydes react with one equivalent of
monohydric alcohol in the presence of dry hydrogen chloride
to yield alkoxyalcohol intermediate, known as hemiacetals,
which further react with one more molecule of alcohol to
give a gem-dialkoxy
compound known as
acetal as shown in the
reaction Ketones react with
ethylene glycol under
similar conditions to form
cyclic products known as
ethylene glycol ketals Dry hydrogen chloride
protonates the oxygen of
the carbonyl compounds
and therefore, increases
the electrophilicity of the
carbonyl carbon facilitating
Rationalised 2023-24
238
Chemistry
the nucleophilic attack of ethylene glycol |
1 | 6670-6673 | (d) Addition of alcohols: Aldehydes react with one equivalent of
monohydric alcohol in the presence of dry hydrogen chloride
to yield alkoxyalcohol intermediate, known as hemiacetals,
which further react with one more molecule of alcohol to
give a gem-dialkoxy
compound known as
acetal as shown in the
reaction Ketones react with
ethylene glycol under
similar conditions to form
cyclic products known as
ethylene glycol ketals Dry hydrogen chloride
protonates the oxygen of
the carbonyl compounds
and therefore, increases
the electrophilicity of the
carbonyl carbon facilitating
Rationalised 2023-24
238
Chemistry
the nucleophilic attack of ethylene glycol Acetals and ketals
are hydrolysed with aqueous mineral acids to yield
corresponding aldehydes and ketones respectively |
1 | 6671-6674 | Ketones react with
ethylene glycol under
similar conditions to form
cyclic products known as
ethylene glycol ketals Dry hydrogen chloride
protonates the oxygen of
the carbonyl compounds
and therefore, increases
the electrophilicity of the
carbonyl carbon facilitating
Rationalised 2023-24
238
Chemistry
the nucleophilic attack of ethylene glycol Acetals and ketals
are hydrolysed with aqueous mineral acids to yield
corresponding aldehydes and ketones respectively (e) Addition of ammonia and its derivatives: Nucleophiles, such
as ammonia and its derivatives H2N-Z add to the carbonyl
group of aldehydes and ketones |
1 | 6672-6675 | Dry hydrogen chloride
protonates the oxygen of
the carbonyl compounds
and therefore, increases
the electrophilicity of the
carbonyl carbon facilitating
Rationalised 2023-24
238
Chemistry
the nucleophilic attack of ethylene glycol Acetals and ketals
are hydrolysed with aqueous mineral acids to yield
corresponding aldehydes and ketones respectively (e) Addition of ammonia and its derivatives: Nucleophiles, such
as ammonia and its derivatives H2N-Z add to the carbonyl
group of aldehydes and ketones The reaction is reversible
and catalysed by acid |
1 | 6673-6676 | Acetals and ketals
are hydrolysed with aqueous mineral acids to yield
corresponding aldehydes and ketones respectively (e) Addition of ammonia and its derivatives: Nucleophiles, such
as ammonia and its derivatives H2N-Z add to the carbonyl
group of aldehydes and ketones The reaction is reversible
and catalysed by acid The
equilibrium
favours the product
formation due to rapid
dehydration of the
intermediate to form
>C=N-Z |
1 | 6674-6677 | (e) Addition of ammonia and its derivatives: Nucleophiles, such
as ammonia and its derivatives H2N-Z add to the carbonyl
group of aldehydes and ketones The reaction is reversible
and catalysed by acid The
equilibrium
favours the product
formation due to rapid
dehydration of the
intermediate to form
>C=N-Z Z = Alkyl, aryl, OH, NH2, C6H5NH, NHCONH2, etc |
1 | 6675-6678 | The reaction is reversible
and catalysed by acid The
equilibrium
favours the product
formation due to rapid
dehydration of the
intermediate to form
>C=N-Z Z = Alkyl, aryl, OH, NH2, C6H5NH, NHCONH2, etc Table 8 |
1 | 6676-6679 | The
equilibrium
favours the product
formation due to rapid
dehydration of the
intermediate to form
>C=N-Z Z = Alkyl, aryl, OH, NH2, C6H5NH, NHCONH2, etc Table 8 2: Some N-Substituted Derivatives of Aldehydes and Ketones (>C=N-Z)
-H
Ammonia
Imine
-R
Amine
—OH
Hydroxylamine
Oxime
—NH2
Hydrazine
Hydrazone
Phenylhydrazine
Phenylhydrazone
Z
Reagent name
Carbonyl derivative
Product name
Substituted imine
(Schiff’s base)
* 2,4-DNP-derivatives are yellow, orange or red solids, useful for characterisation of aldehydes and ketones |
1 | 6677-6680 | Z = Alkyl, aryl, OH, NH2, C6H5NH, NHCONH2, etc Table 8 2: Some N-Substituted Derivatives of Aldehydes and Ketones (>C=N-Z)
-H
Ammonia
Imine
-R
Amine
—OH
Hydroxylamine
Oxime
—NH2
Hydrazine
Hydrazone
Phenylhydrazine
Phenylhydrazone
Z
Reagent name
Carbonyl derivative
Product name
Substituted imine
(Schiff’s base)
* 2,4-DNP-derivatives are yellow, orange or red solids, useful for characterisation of aldehydes and ketones 2,4-Dinitrophenyl-
2,4 Dinitrophenyl-
Semicarbazide
Semicarbazone
2 |
1 | 6678-6681 | Table 8 2: Some N-Substituted Derivatives of Aldehydes and Ketones (>C=N-Z)
-H
Ammonia
Imine
-R
Amine
—OH
Hydroxylamine
Oxime
—NH2
Hydrazine
Hydrazone
Phenylhydrazine
Phenylhydrazone
Z
Reagent name
Carbonyl derivative
Product name
Substituted imine
(Schiff’s base)
* 2,4-DNP-derivatives are yellow, orange or red solids, useful for characterisation of aldehydes and ketones 2,4-Dinitrophenyl-
2,4 Dinitrophenyl-
Semicarbazide
Semicarbazone
2 Reduction
(i) Reduction to alcohols: Aldehydes and ketones are reduced to
primary and secondary alcohols respectively by sodium
borohydride (NaBH4) or lithium aluminium hydride (LiAlH4) as
well as by catalytic hydrogenation (Unit 7, Class XII) |
1 | 6679-6682 | 2: Some N-Substituted Derivatives of Aldehydes and Ketones (>C=N-Z)
-H
Ammonia
Imine
-R
Amine
—OH
Hydroxylamine
Oxime
—NH2
Hydrazine
Hydrazone
Phenylhydrazine
Phenylhydrazone
Z
Reagent name
Carbonyl derivative
Product name
Substituted imine
(Schiff’s base)
* 2,4-DNP-derivatives are yellow, orange or red solids, useful for characterisation of aldehydes and ketones 2,4-Dinitrophenyl-
2,4 Dinitrophenyl-
Semicarbazide
Semicarbazone
2 Reduction
(i) Reduction to alcohols: Aldehydes and ketones are reduced to
primary and secondary alcohols respectively by sodium
borohydride (NaBH4) or lithium aluminium hydride (LiAlH4) as
well as by catalytic hydrogenation (Unit 7, Class XII) (ii) Reduction to hydrocarbons: The carbonyl group of aldehydes
and ketones is reduced to CH2 group on treatment with zinc-
amalgam and concentrated hydrochloric acid [Clemmensen
hydrazone
hydrazine
Rationalised 2023-24
239
Aldehydes, Ketones and Carboxylic Acids
reduction] or with hydrazine followed by heating with sodium
or potassium hydroxide in high boiling solvent such as ethylene
glycol (Wolff-Kishner reduction) |
1 | 6680-6683 | 2,4-Dinitrophenyl-
2,4 Dinitrophenyl-
Semicarbazide
Semicarbazone
2 Reduction
(i) Reduction to alcohols: Aldehydes and ketones are reduced to
primary and secondary alcohols respectively by sodium
borohydride (NaBH4) or lithium aluminium hydride (LiAlH4) as
well as by catalytic hydrogenation (Unit 7, Class XII) (ii) Reduction to hydrocarbons: The carbonyl group of aldehydes
and ketones is reduced to CH2 group on treatment with zinc-
amalgam and concentrated hydrochloric acid [Clemmensen
hydrazone
hydrazine
Rationalised 2023-24
239
Aldehydes, Ketones and Carboxylic Acids
reduction] or with hydrazine followed by heating with sodium
or potassium hydroxide in high boiling solvent such as ethylene
glycol (Wolff-Kishner reduction) 3 |
1 | 6681-6684 | Reduction
(i) Reduction to alcohols: Aldehydes and ketones are reduced to
primary and secondary alcohols respectively by sodium
borohydride (NaBH4) or lithium aluminium hydride (LiAlH4) as
well as by catalytic hydrogenation (Unit 7, Class XII) (ii) Reduction to hydrocarbons: The carbonyl group of aldehydes
and ketones is reduced to CH2 group on treatment with zinc-
amalgam and concentrated hydrochloric acid [Clemmensen
hydrazone
hydrazine
Rationalised 2023-24
239
Aldehydes, Ketones and Carboxylic Acids
reduction] or with hydrazine followed by heating with sodium
or potassium hydroxide in high boiling solvent such as ethylene
glycol (Wolff-Kishner reduction) 3 Oxidation
Aldehydes differ from ketones in their oxidation reactions |
1 | 6682-6685 | (ii) Reduction to hydrocarbons: The carbonyl group of aldehydes
and ketones is reduced to CH2 group on treatment with zinc-
amalgam and concentrated hydrochloric acid [Clemmensen
hydrazone
hydrazine
Rationalised 2023-24
239
Aldehydes, Ketones and Carboxylic Acids
reduction] or with hydrazine followed by heating with sodium
or potassium hydroxide in high boiling solvent such as ethylene
glycol (Wolff-Kishner reduction) 3 Oxidation
Aldehydes differ from ketones in their oxidation reactions Aldehydes
are easily oxidised to carboxylic acids on treatment with common
oxidising agents like nitric acid, potassium permanganate, potassium
dichromate, etc |
1 | 6683-6686 | 3 Oxidation
Aldehydes differ from ketones in their oxidation reactions Aldehydes
are easily oxidised to carboxylic acids on treatment with common
oxidising agents like nitric acid, potassium permanganate, potassium
dichromate, etc Even mild oxidising agents, mainly Tollens’ reagent
and Fehlings’ reagent also oxidise aldehydes |
1 | 6684-6687 | Oxidation
Aldehydes differ from ketones in their oxidation reactions Aldehydes
are easily oxidised to carboxylic acids on treatment with common
oxidising agents like nitric acid, potassium permanganate, potassium
dichromate, etc Even mild oxidising agents, mainly Tollens’ reagent
and Fehlings’ reagent also oxidise aldehydes Ketones are generally oxidised under vigorous conditions, i |
1 | 6685-6688 | Aldehydes
are easily oxidised to carboxylic acids on treatment with common
oxidising agents like nitric acid, potassium permanganate, potassium
dichromate, etc Even mild oxidising agents, mainly Tollens’ reagent
and Fehlings’ reagent also oxidise aldehydes Ketones are generally oxidised under vigorous conditions, i e |
1 | 6686-6689 | Even mild oxidising agents, mainly Tollens’ reagent
and Fehlings’ reagent also oxidise aldehydes Ketones are generally oxidised under vigorous conditions, i e ,
strong oxidising agents and at elevated temperatures |
1 | 6687-6690 | Ketones are generally oxidised under vigorous conditions, i e ,
strong oxidising agents and at elevated temperatures Their oxidation
involves carbon-carbon bond cleavage to afford a mixture of carboxylic
acids having lesser number of carbon atoms than the parent ketone |
1 | 6688-6691 | e ,
strong oxidising agents and at elevated temperatures Their oxidation
involves carbon-carbon bond cleavage to afford a mixture of carboxylic
acids having lesser number of carbon atoms than the parent ketone The mild oxidising agents given below are used to distinguish
aldehydes from ketones:
(i) Tollens’ test: On warming an aldehyde with freshly prepared
ammoniacal silver nitrate solution (Tollens’ reagent), a bright
silver mirror is produced due to the formation of silver metal |
1 | 6689-6692 | ,
strong oxidising agents and at elevated temperatures Their oxidation
involves carbon-carbon bond cleavage to afford a mixture of carboxylic
acids having lesser number of carbon atoms than the parent ketone The mild oxidising agents given below are used to distinguish
aldehydes from ketones:
(i) Tollens’ test: On warming an aldehyde with freshly prepared
ammoniacal silver nitrate solution (Tollens’ reagent), a bright
silver mirror is produced due to the formation of silver metal The aldehydes are oxidised to corresponding carboxylate anion |
1 | 6690-6693 | Their oxidation
involves carbon-carbon bond cleavage to afford a mixture of carboxylic
acids having lesser number of carbon atoms than the parent ketone The mild oxidising agents given below are used to distinguish
aldehydes from ketones:
(i) Tollens’ test: On warming an aldehyde with freshly prepared
ammoniacal silver nitrate solution (Tollens’ reagent), a bright
silver mirror is produced due to the formation of silver metal The aldehydes are oxidised to corresponding carboxylate anion The reaction occurs in alkaline medium |
1 | 6691-6694 | The mild oxidising agents given below are used to distinguish
aldehydes from ketones:
(i) Tollens’ test: On warming an aldehyde with freshly prepared
ammoniacal silver nitrate solution (Tollens’ reagent), a bright
silver mirror is produced due to the formation of silver metal The aldehydes are oxidised to corresponding carboxylate anion The reaction occurs in alkaline medium (ii) Fehling’s test: Fehling reagent comprises of two solutions,
Fehling solution A and Fehling solution B |
1 | 6692-6695 | The aldehydes are oxidised to corresponding carboxylate anion The reaction occurs in alkaline medium (ii) Fehling’s test: Fehling reagent comprises of two solutions,
Fehling solution A and Fehling solution B Fehling solution A is
aqueous copper sulphate and Fehling solution B is alkaline
sodium potassium tartarate (Rochelle salt) |
1 | 6693-6696 | The reaction occurs in alkaline medium (ii) Fehling’s test: Fehling reagent comprises of two solutions,
Fehling solution A and Fehling solution B Fehling solution A is
aqueous copper sulphate and Fehling solution B is alkaline
sodium potassium tartarate (Rochelle salt) These two solutions
are mixed in equal amounts before test |
1 | 6694-6697 | (ii) Fehling’s test: Fehling reagent comprises of two solutions,
Fehling solution A and Fehling solution B Fehling solution A is
aqueous copper sulphate and Fehling solution B is alkaline
sodium potassium tartarate (Rochelle salt) These two solutions
are mixed in equal amounts before test On heating an aldehyde
with Fehling’s reagent, a reddish brown precipitate is obtained |
1 | 6695-6698 | Fehling solution A is
aqueous copper sulphate and Fehling solution B is alkaline
sodium potassium tartarate (Rochelle salt) These two solutions
are mixed in equal amounts before test On heating an aldehyde
with Fehling’s reagent, a reddish brown precipitate is obtained Aldehydes are oxidised to corresponding carboxylate anion |
1 | 6696-6699 | These two solutions
are mixed in equal amounts before test On heating an aldehyde
with Fehling’s reagent, a reddish brown precipitate is obtained Aldehydes are oxidised to corresponding carboxylate anion Aromatic aldehydes do not respond to this test |
1 | 6697-6700 | On heating an aldehyde
with Fehling’s reagent, a reddish brown precipitate is obtained Aldehydes are oxidised to corresponding carboxylate anion Aromatic aldehydes do not respond to this test Bernhard Tollens
(1841-1918) was a
Professor of Chemistry
at the University of
Gottingen, Germany |
1 | 6698-6701 | Aldehydes are oxidised to corresponding carboxylate anion Aromatic aldehydes do not respond to this test Bernhard Tollens
(1841-1918) was a
Professor of Chemistry
at the University of
Gottingen, Germany Rationalised 2023-24
240
Chemistry
Example 8 |
1 | 6699-6702 | Aromatic aldehydes do not respond to this test Bernhard Tollens
(1841-1918) was a
Professor of Chemistry
at the University of
Gottingen, Germany Rationalised 2023-24
240
Chemistry
Example 8 4
Example 8 |
1 | 6700-6703 | Bernhard Tollens
(1841-1918) was a
Professor of Chemistry
at the University of
Gottingen, Germany Rationalised 2023-24
240
Chemistry
Example 8 4
Example 8 4
Example 8 |
1 | 6701-6704 | Rationalised 2023-24
240
Chemistry
Example 8 4
Example 8 4
Example 8 4
Example 8 |
1 | 6702-6705 | 4
Example 8 4
Example 8 4
Example 8 4
Example 8 |
1 | 6703-6706 | 4
Example 8 4
Example 8 4
Example 8 4
An organic compound (A) with molecular formula C8H8O forms an
orange-red precipitate with 2,4-DNP reagent and gives yellow
precipitate on heating with iodine in the presence of sodium
hydroxide |
1 | 6704-6707 | 4
Example 8 4
Example 8 4
An organic compound (A) with molecular formula C8H8O forms an
orange-red precipitate with 2,4-DNP reagent and gives yellow
precipitate on heating with iodine in the presence of sodium
hydroxide It neither reduces Tollens’ or Fehlings’ reagent, nor does
it decolourise bromine water or Baeyer’s reagent |
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