Amines are less reactive in substitution reactions. Their reactivity is much lesser than alcohols and alkylflourides towards substitution. Protonation of the amino group makes it a better leaving group, but not nearly as good a leaving group as a protonated alcohol. Protonated amino groups cannot be displaced by `OH^(-)` because it would react immediately with the acidic hydrogen which would convert it in to a poor nucleophile.
The leaving group in quartenary ammonium ion has about the same leaving tendency as a protonated amino group but does not have acidic hydrogen. The reaction of a quartenary ammonium ion with hydroxide ion is known as Hoffmann elimination reaction. The leaving group is tertiary amine. Since a tertiary amine is only a moderately good leaving group, the reaction requires heat. The carbon to which the tertiary amine is attached is designated as `alpha` carbon.
When the hydroxide ion starts to remove a `beta` H from a quartenary ammonium ion, the leaving group does not immediately start to leave because a tertiary amine is not a good leaving group. As a result, a partial negative charge builds up on the carbon from which the proton is removed.
Which of the following statements is correct?
Amines are less reactive in substitution reactions. Their reactivity is much lesser than alcohols and alkylflourides towards substitution. Protonation of the amino group makes it a better leaving group, but not nearly as good a leaving group as a protonated alcohol. Protonated amino groups cannot be displaced by `OH^(-)` because it would react immediately with the acidic hydrogen which would convert it in to a poor nucleophile.
The leaving group in quartenary ammonium ion has about the same leaving tendency as a protonated amino group but does not have acidic hydrogen. The reaction of a quartenary ammonium ion with hydroxide ion is known as Hoffmann elimination reaction. The leaving group is tertiary amine. Since a tertiary amine is only a moderately good leaving group, the reaction requires heat. The carbon to which the tertiary amine is attached is designated as `alpha` carbon.
When the hydroxide ion starts to remove a `beta` H from a quartenary ammonium ion, the leaving group does not immediately start to leave because a tertiary amine is not a good leaving group. As a result, a partial negative charge builds up on the carbon from which the proton is removed.
Which of the following statements is correct?
The leaving group in quartenary ammonium ion has about the same leaving tendency as a protonated amino group but does not have acidic hydrogen. The reaction of a quartenary ammonium ion with hydroxide ion is known as Hoffmann elimination reaction. The leaving group is tertiary amine. Since a tertiary amine is only a moderately good leaving group, the reaction requires heat. The carbon to which the tertiary amine is attached is designated as `alpha` carbon.
When the hydroxide ion starts to remove a `beta` H from a quartenary ammonium ion, the leaving group does not immediately start to leave because a tertiary amine is not a good leaving group. As a result, a partial negative charge builds up on the carbon from which the proton is removed.
Which of the following statements is correct?
A
`PK_(n)` value of protonated amine is more than that of protonated alcohol
B
`PK_(a)` valued of the protonated amine is less than that of protonated alcohol
C
`PK_(a)` value for protonated amine is equals to that protonated alcohol
D
`PK_(a)` value of amine is less than that of alcohol
Text Solution
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The correct Answer is:
A
`P^(ka)` : Protonated amine `gt` Protonated alchol
Alchols more acidic than amines
Alchols more acidic than amines
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Amines are less reactive in substitution reactions. Their reactivity is much lesser than alcohols and alkylflourides towards substitution. Protonation of the amino group makes it a better leaving group, but not nearly as good a leaving group as a protonated alcohol. Protonated amino groups cannot be displaced by OH^(-) because it would react immediately with the acidic hydrogen which would convert it in to a poor nucleophile. The leaving group in quartenary ammonium ion has about the same leaving tendency as a protonated amino group but does not have acidic hydrogen. The reaction of a quartenary ammonium ion with hydroxide ion is known as Hoffmann elimination reaction. The leaving group is tertiary amine. Since a tertiary amine is only a moderately good leaving group, the reaction requires heat. The carbon to which the tertiary amine is attached is designated as alpha carbon. When the hydroxide ion starts to remove a beta H from a quartenary ammonium ion, the leaving group does not immediately start to leave because a tertiary amine is not a good leaving group. As a result, a partial negative charge builds up on the carbon from which the proton is removed. Which of the following statements are true regarding Hoffmann elimination ?
Amines are less reactive in substitution reactions. Their reactivity is much lesser than alcohols and alkylflourides towards substitution. Protonation of the amino group makes it a better leaving group, but not nearly as good a leaving group as a protonated alcohol. Protonated amino groups cannot be displaced by OH^(-) because it would react immediately with the acidic hydrogen which would convert it in to a poor nucleophile. The leaving group in quartenary ammonium ion has about the same leaving tendency as a protonated amino group but does not have acidic hydrogen. The reaction of a quartenary ammonium ion with hydroxide ion is known as Hoffmann elimination reaction. The leaving group is tertiary amine. Since a tertiary amine is only a moderately good leaving group, the reaction requires heat. The carbon to which the tertiary amine is attached is designated as alpha carbon. When the hydroxide ion starts to remove a beta H from a quartenary ammonium ion, the leaving group does not immediately start to leave because a tertiary amine is not a good leaving group. As a result, a partial negative charge builds up on the carbon from which the proton is removed. The compounds 'C' in question number 31 on heating with moist silver oxide gives
In L-Phenyl alanine the amino group lies at
In benzyl amine amino group is a
Primary amino group is absent in
Primary amino group is absent in
Aryl halides are less reactive towards nucleophilic substitution reaction as compared to alkyl halides due to
Knowledge Check
Amines are less reactive in substitution reactions. Their reactivity is much lesser than alcohols and alkylflourides towards substitution. Protonation of the amino group makes it a better leaving group, but not nearly as good a leaving group as a protonated alcohol. Protonated amino groups cannot be displaced by OH^(-) because it would react immediately with the acidic hydrogen which would convert it in to a poor nucleophile. The leaving group in quartenary ammonium ion has about the same leaving tendency as a protonated amino group but does not have acidic hydrogen. The reaction of a quartenary ammonium ion with hydroxide ion is known as Hoffmann elimination reaction. The leaving group is tertiary amine. Since a tertiary amine is only a moderately good leaving group, the reaction requires heat. The carbon to which the tertiary amine is attached is designated as alpha carbon. When the hydroxide ion starts to remove a beta H from a quartenary ammonium ion, the leaving group does not immediately start to leave because a tertiary amine is not a good leaving group. As a result, a partial negative charge builds up on the carbon from which the proton is removed. Which of the following statements are true regarding Hoffmann elimination ?
Amines are less reactive in substitution reactions. Their reactivity is much lesser than alcohols and alkylflourides towards substitution. Protonation of the amino group makes it a better leaving group, but not nearly as good a leaving group as a protonated alcohol. Protonated amino groups cannot be displaced by OH^(-) because it would react immediately with the acidic hydrogen which would convert it in to a poor nucleophile. The leaving group in quartenary ammonium ion has about the same leaving tendency as a protonated amino group but does not have acidic hydrogen. The reaction of a quartenary ammonium ion with hydroxide ion is known as Hoffmann elimination reaction. The leaving group is tertiary amine. Since a tertiary amine is only a moderately good leaving group, the reaction requires heat. The carbon to which the tertiary amine is attached is designated as alpha carbon. When the hydroxide ion starts to remove a beta H from a quartenary ammonium ion, the leaving group does not immediately start to leave because a tertiary amine is not a good leaving group. As a result, a partial negative charge builds up on the carbon from which the proton is removed. Which of the following statements are true regarding Hoffmann elimination ?
A
it follows anti-zaitsev elimination
B
it forms only zaitsev product
C
no polar compounds are formed at the end of the reaction
D
it is given by only `1^(0)` amines
Amines are less reactive in substitution reactions. Their reactivity is much lesser than alcohols and alkylflourides towards substitution. Protonation of the amino group makes it a better leaving group, but not nearly as good a leaving group as a protonated alcohol. Protonated amino groups cannot be displaced by OH^(-) because it would react immediately with the acidic hydrogen which would convert it in to a poor nucleophile. The leaving group in quartenary ammonium ion has about the same leaving tendency as a protonated amino group but does not have acidic hydrogen. The reaction of a quartenary ammonium ion with hydroxide ion is known as Hoffmann elimination reaction. The leaving group is tertiary amine. Since a tertiary amine is only a moderately good leaving group, the reaction requires heat. The carbon to which the tertiary amine is attached is designated as alpha carbon. When the hydroxide ion starts to remove a beta H from a quartenary ammonium ion, the leaving group does not immediately start to leave because a tertiary amine is not a good leaving group. As a result, a partial negative charge builds up on the carbon from which the proton is removed. Which of the following compounds when subjected to Hoffmann elimination gives an alkene which can exhibit geometrical isomerism ?
Amines are less reactive in substitution reactions. Their reactivity is much lesser than alcohols and alkylflourides towards substitution. Protonation of the amino group makes it a better leaving group, but not nearly as good a leaving group as a protonated alcohol. Protonated amino groups cannot be displaced by OH^(-) because it would react immediately with the acidic hydrogen which would convert it in to a poor nucleophile. The leaving group in quartenary ammonium ion has about the same leaving tendency as a protonated amino group but does not have acidic hydrogen. The reaction of a quartenary ammonium ion with hydroxide ion is known as Hoffmann elimination reaction. The leaving group is tertiary amine. Since a tertiary amine is only a moderately good leaving group, the reaction requires heat. The carbon to which the tertiary amine is attached is designated as alpha carbon. When the hydroxide ion starts to remove a beta H from a quartenary ammonium ion, the leaving group does not immediately start to leave because a tertiary amine is not a good leaving group. As a result, a partial negative charge builds up on the carbon from which the proton is removed. Which of the following compounds when subjected to Hoffmann elimination gives an alkene which can exhibit geometrical isomerism ?
A
B
C
D
none
Amines are less reactive in substitution reactions. Their reactivity is much lesser than alcohols and alkylflourides towards substitution. Protonation of the amino group makes it a better leaving group, but not nearly as good a leaving group as a protonated alcohol. Protonated amino groups cannot be displaced by OH^(-) because it would react immediately with the acidic hydrogen which would convert it in to a poor nucleophile. The leaving group in quartenary ammonium ion has about the same leaving tendency as a protonated amino group but does not have acidic hydrogen. The reaction of a quartenary ammonium ion with hydroxide ion is known as Hoffmann elimination reaction. The leaving group is tertiary amine. Since a tertiary amine is only a moderately good leaving group, the reaction requires heat. The carbon to which the tertiary amine is attached is designated as alpha carbon. When the hydroxide ion starts to remove a beta H from a quartenary ammonium ion, the leaving group does not immediately start to leave because a tertiary amine is not a good leaving group. As a result, a partial negative charge builds up on the carbon from which the proton is removed. Which Compounds of question number 31 are optically acitve?
Amines are less reactive in substitution reactions. Their reactivity is much lesser than alcohols and alkylflourides towards substitution. Protonation of the amino group makes it a better leaving group, but not nearly as good a leaving group as a protonated alcohol. Protonated amino groups cannot be displaced by OH^(-) because it would react immediately with the acidic hydrogen which would convert it in to a poor nucleophile. The leaving group in quartenary ammonium ion has about the same leaving tendency as a protonated amino group but does not have acidic hydrogen. The reaction of a quartenary ammonium ion with hydroxide ion is known as Hoffmann elimination reaction. The leaving group is tertiary amine. Since a tertiary amine is only a moderately good leaving group, the reaction requires heat. The carbon to which the tertiary amine is attached is designated as alpha carbon. When the hydroxide ion starts to remove a beta H from a quartenary ammonium ion, the leaving group does not immediately start to leave because a tertiary amine is not a good leaving group. As a result, a partial negative charge builds up on the carbon from which the proton is removed. Which Compounds of question number 31 are optically acitve?
A
A and B
B
B and C
C
A, B and C
D
All are inactive
AAKASH SERIES-AMINES AND AZO COMPOUNDS -PRACTICE SHEET - 5 (Linked Comprehension type questions) Passage - I
- Amines are less reactive in substitution reactions. Their reactivity i...
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- Amines are less reactive in substitution reactions. Their reactivity i...
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- Amines are less reactive in substitution reactions. Their reactivity i...
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- Amines are less reactive in substitution reactions. Their reactivity i...
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- Amines are less reactive in substitution reactions. Their reactivity i...
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