Amines Chemistry - Amines

Accomplish the following conversion:
Aniline to 2, 4, 6 -tribromofluorobenzene.

Accomplish the following conversion:
Nitrobenzene to benzoic acid.

Accomplish the following conversion:
Benzamide to toluene

Write the reactions of (i) aromatic and (ii) aliphatic primary amines with nitrous acid.

Give reasons for the following:

1. Acetylation of aniline reduces its activation effect.
2. CH₃NH₂ is more basic than C₆H₅NH₂.
3. Although -NH₂ is o/p directing group, yet aniline on nitration gives a significant amount of m-nitroaniline.

Give reasons for the following :

1. Acetylation of aniline reduces its activation effect.
2. CH₃NH₂ is more basic than C₆H₅NH₂.
3. Although -NH2 is o/p directing group, yet aniline on nitration gives a significant amount of m-nitroaniline.

Give reasons for the following:

1. Aniline does not undergo Friedal-Crafts reaction.
2. (CH₃)₂ NH is more basic than (CH₃)₃ N in an aqueous solution.
3. Primary amines have higher boiling point than tertiary amines.

Give reasons for the following:

1. Acetylation of aniline reduces its activation effect.
2. CH₃NH₂ is more basic than C₆H₅NH₂.
3. Although -NH₂ is o/p directing group, yet aniline on nitration gives a significant amount of m-nitroaniline.

Give a chemical test to distinguish between a primary and a secondary amine.

How will you convert:
Methanol to ethanoic acid.

Give plausible explanation for each of the following:
Why are aliphatic amines stronger bases than aromatic amines?

Write short notes on the following:
Gabriel phthalimide synthesis.

How will you convert:
Hexanenitrile into 1-aminopentane.

Read the passage given below and answer the following questions:
Amines are alkyl or aryl derivatives of ammonia formed by replacement of one or more hydrogen atoms. Alkyl derivatives are called aliphatic amines and aryl derivatives are known as aromatic amines. The presence of aromatic amines can be identified by performing dye test. Aniline is the simplest example of aromatic amine. It undergoeselectrophilic substitution reactions in which -NH₂ group strongly activates the aromatic ring through delocalisation of lone pair of electrons of N-atom. Aniline undergoes electrophilic substitution reactions. Ortho and para positions to the -NH₂ group become centres of high electrons density. Thus, -NH₂ group is ortho and para-directing and powerful activating group.
The following questions are multiple choice questions. Choose the most appropriate answer:

1. Cyclohexylamine and aniline can be distinguished by:

1. Hinsberg test.
2. carbylamine test.
3. Lassaigne test.
4. azo dye test.

2. Which of the following compounds gives dye test?

1. Aniline.
2. Methyl amine.
3. Diphenyl amine.
4. Ethyl amine.

3. Aniline when acetylated, the major product on nitration followed by alkaline hydrolysis gives:

1.  Acetanilide.
2. o-nitroacetanitide.
3. p-nitroaniline.
4. m-nitroanitine.

4. Oxidation of aniline with manganese dioxide and sulphuric acid produces:

1. Phenylhydroxylamine.
2. Nitrobenzene.
3. p-benzoquinone.
4. Phenol.

5. Aniline when treated with cone. HNO₃ and H₂S0₄ gives:

1.  p-phenylenediamine.
2. m-nitroaniline.
3. p-benzoquinone.
4. Nitrobenzene.

Read the passage given below and answer the following questions:
The amines are basic in nature due to the presence of a lone pair of electron on N-atom of the -NH₂ group, which it can donate to electron deficient compounds. Aliphatic amines are stronger bases than NH₃ because of the +I effect of the alkyl groups. Greater the number of alkyl groups attached to N-atom, higher is the electron density on it and more will be the basicity. Thus, the order of basic nature of amines is expected to be 3º > 2º > 1º, however the observed order is 2º > 1º > 3º. This is explained on the basis of crowding on N-atom of the amine by alkyl groups which hinders the approach and bonding by a proton, consequently, the electron pair which is present on N is unavailable for donation and hence 3º amines are the weakest bases.
Aromatic amines are weaker bases than ammonia and aliphatic amines. Electron-donating groups such as -CH₃, -OCH₃, etc. increase the basicity while electron-withdrawing substitutes such as -NO₂, -CN, halogens, etc. decrease the basicity of amines. The effect of these substituents is more at p than at m-positions.
The following questions are multiple choice questions. Choose the most appropriate answer:

1. Which one of the following is the strongest base in aqueous solution?

1. Methyl amine.
2. Tri methyl amine.
3. Aniline.
4. Dimethyl amine.

2. Which order ofbasicity is correct?

1. Aniline > m-toluidine > o-toluidine
2. Aniline> o-toluidine > m-toluidine
3. o-toluidine > aniline> m-toluidine
4. o-toluidine < aniline < m-toluidine

3. What is the decreasing order of basicity of primary, secondary and tertiary ethylamines and NH₃?

1. NH₃ > C₂H₅NH₂ > (C₂H₅)₂NH > (C₂H₅)₃N
   
2. (C₂H₅)₃N > (C₂H₅)₂NH > C₂H₅NH₂ > NH₃
   
3. (C₂H₅)₂NH > C₂H₅NH₂> (C₂H₅)₃N > NH₃
   
4. (C₂H₅)₂NH > (C₂H₅)₃N > C₂H₅NH₂ > NH₃
   

4. The order of basic strength among the following amines in benzene solution is:

1. CH₃NH₂ > (CH₃)₃N > (CH₃)₂NH
   
2. (CH₃)₃N > (CH₃)₂NH > CH₃NH₂
   
3. CH₃NH₂ > (CH₃)₂NH > (CH₃)₃N
   
4. (CH₃)₃N > CH₃NH₂ > (CH₃)₂NH
   

5. Choose the correct statement.

1. Methylamine is slightly acidic.
2. Methylamine is less basic than ammonia.
3. Methylamine is a stronger base than ammonia.
4. Methylamine forms salts with alkalies.

Read the passage given below and answer the following questions:

Amines are produced when an alcoholic solution of ammonia and an alkyl or a benzyl halide is heated in a sealed tube at 373K. This reaction is called ammonolysis and usually gives a mixture of primary, secondary and tertiary amines along with some quarternary ammonium salts. This reaction is an example of nucleophilic substitution reaction in which ammonia acts as a nucleophile due to the presence of a lone pair of electrons on the nitrogen atom. However this method cannot be used for the preparation of aryl amines. One of the most convenient methods for the preparation of aryl amines is reduction of nitro compounds. Aryl amines can also be prepared by reduction of nitrites or Gabriel phthalimide synthesis.

A statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.

1. Assertion and reason both are correct statements and reason is correct explanation for assertion.
2. Assertion and reason both are correct statements but reason is not correct explanation for assertion.
3. Assertion is correct statement but reason is wrong statement.
4. Assertion is wrong statement but reason is correct statement.

1. Assertion: Ammonolysis of alkyl halides only produces 2° amines.

Reason: Ammonolysis of alkyl halides involves the reaction between alkyl halides and alcoholic ammonia.

2. Assertion: Gabriel-phthalimide reaction can be used to prepare both aryl and alkyl primary amines.

Reason: Aryl halides are more reactive alkyl halides towards nucleophilic substitution reactions.

3. Assertion: Anunonolysis method cannot be used for the preparation of aryl amines.

Reason: Aryl halides are much less reactive than alkyl halides towards nucleophilic substitution reaction.

4. Assertion: Ammonolysis can be used to prepare pure primary amines.

Reason: Ammonolysis of haloalkanes lead to multiple ammonium salts.

5. Assertion: Aromatic 1º amines can not be prepared by Gabriel phthalimide synthesis.

Reason: Aryl halides do not undergo nucleophilic substitution with anion formed by phthalimide.

Read the passage given below and answer the following questions:
A mixture of two aromatic compounds (A) and (B) was separated by dissolving in chloroform followed by extraction with aqueous KOH solution. The organic layer containing compound (A), when heated with alcoholic solution of KOH produce C₇H₅N (C) associated with unpleasant odour.
The following questions are multiple choice questions. Choose the most appropriate answer:

1. What is A?

1. C₆H₅NH₂
2. C₆H₅CH₃
3. C₆H₅CH₃
4. None of these.

2. The reaction of (A) with alcoholic solution of KOH to produce (C) of unpleasant odour is called:

1. Sandmeyer reaction.
2. Carbylamine reaction.
3. Ullmann reaction.
4. Reimer-Tiemann reaction..

3. The alkaline aqueous layer (B) when heated with chloroform and then acidified give a mixture of isomeric compounds of molecular formula C₇H₆O₂. (B) is:

1. C₆H₅CHO
2. C₆H₅COOH
3. C₆H₅CH₃
4. C₆H₅OH

4. In the chemical reaction, CH₃CH₂NH₂ + CHCl₃ + 3KOH → (A)+ (B) + 3H₂O,

1. C₂H₅NC and KCl
2. C₂H₅CN and KCl
3. CH₃CH₂CONH₂ and KCl
4. C₂H₅NC and K₂CO₃

5. Direct nitration of an aromatic compound (A) is not feasible because:

1. The reaction cannot be stopped at the mononitration stage.
2. A mixture of o, m and p-nitroaniline is always obtained.
3. Nitric acid oxidises most of the aromatic compound to give oxidation products along with only a small amount of nitrated products.
4. All of the above.

Out of the following, the strongest base in aqueous solution is:

Arrange the following compounds in increasing order of basicity:
CH₃​NH₂​, (CH₃​)₂​NH, NH₃​ ,C₆​H₅​NH₂​

Which of the following is more appropriate reason for aniline being less basic than aliphatic amines?

Diphenyl hydrazine is same as:

Which of the following is a primary arylalkyl amine?

In these questions, a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.

1. Assertion and reason both are correct statements and reason is correct explanation for assertion.
2. Assertion and reason both are correct statements but reason is not correct explanation for assertion.
3. Assertion is correct statement but reason is wrong statement.
4. Assertion is wrong statement but reason is correct statement.

Assertion: Boiling point of amines are lower than those of alcohols and carboxylic acids.
Reason: Amines are much more soluble in water than less polar solvents like alcohol, ether, etc.

Note: In the following question a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.

1. Both assertion and reason are wrong.
2. Both assertion and reason are correct statements but reason is not correct explanation of assertion.
3. Assertion is correct statement but reason is wrong statement.
4. Both assertion and reason are correct statements and reason is correct explanation of assertion.
5. Assertion is wrong statement but reason is correct statement.

Assertion: Acylation of amines gives a monosubstituted product whereas alkylation of amines gives polysubstituted product.
Reason: Acyl group sterically hinders the approach of further acyl groups.

In these questions, a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.

1. Assertion and reason both are correct statements and reason is correct explanation for assertion.
2. Assertion and reason both are correct statements but reason is not correct explanation for assertion.
3. Assertion is correct statement but reason is wrong statement.
4. Assertion is wrong statement but reason is correct statement.

Assertion: Aniline hydrogen sulphate, on heating, forms p-aminosulphonic acid.
Reason: The sulphonic acid group is electron-withdrawing.

In these questions, a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.

1. Assertion and reason both are correct statements and reason is correct explanation for assertion.
2. Assertion and reason both are correct statements but reason is not correct explanation for assertion.
3. Assertion is correct statement but reason is wrong statement.
4. Assertion is wrong statement but reason is correct statement.

Assertion: Nitration of aniline can be done conveniently by protecting the amino group by acetylation.
Reason: Acetylation increases the electron density in the benzene ring.

In these questions, a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.

1. Assertion and reason both are correct statements and reason is correct explanation for assertion.
2. Assertion and reason both are correct statements but reason is not correct explanation for assertion.
3. Assertion is correct statement but reason is wrong statement.
4. Assertion is wrong statement but reason is correct statement.

Assertion: Ammonolysis of alkyl halides involves the reaction between alkyl halides and alcoholic ammonia.
Reason: Reaction can be used to prepare 1º, 2º, 3º amines and finally quaternary ammonium salts.

A colourless substance 'A' (C₆H₇N) is sparingly soluble in water and gives a water soluble compound 'B' on treating with mineral acid. On reacting with CHCl₃ and alcoholic potash 'A' produces an obnoxious smell due to the formation of compound 'C'. Reaction of 'A' with benzenesulphonyl chloride gives compound 'D' which is soluble in alkali. With NaNO₂ and HCl, 'A' forms compound 'E' which reacts with phenol in alkaline medium to give an orange dye 'F'. Identify compounds 'A' to 'F'.

A hydrocarbon ‘A’, (C₄H₈) on reaction with HCl gives a compound ‘B’, (C₄H₉Cl), which on reaction with 1 mol of NH₃ gives compound ‘C’, (C₄H₁₁N). On reacting with NaNO₂ and HCl followed by treatment with water, compound ‘C’ ields an optically active alcohol, ‘D’. Ozonolysis of ‘A’ gives 2 moles of acetaldehyde. Identify the compounds ‘A’ to ‘D’. Explain the reactions involved.

Answer the following questions:
How will you bring about the following conversions?

1. Ethanamine into methanamine.
2. Aniline into 1, 3, 5-tribromobenzene.
3. Aniline into 4-bromoaniline.

A hydrocarbon 'A', (C₄H₈) on reaction with HCl gives a compound 'B', (C₄H₉Cl), which on reaction with 1 mol of NH₃ gives compound 'C', (C₄H₁₁N). On reacting with NaNO₂ and HCl followed by treatment with water, compound 'C' yields an optically active alcohol,'D'. Ozonolysis of 'A' gives 2 mols of acetaldehyde. Identify compounds 'A' to 'D'. Explain the reactions involved.

[A], [B], [C], [D], [E], [F] and [G] are amines each of which forms a hydrochloride containing 32.42% chlorine. [A], [B], [C] and [D] evolve N₂ on reaction with HNO₂, but [E], [F], [G] and [H] do not. Give structures of [A] to [H] with reasons.