Chemistry

Amines

Question:

Which of the following compounds is the weakest Bronsted base?
ncert-exemplar-problems-class-12-chemistry-amines-24

Answer:

(c) Amines (a, b) have stronger tendency to accept a proton and hence are stronger Bronsted bases than phenol (c) and alcohol (d). Since phenol is more acidic than alcohol, therefore, phenol (c) has the least tendency to accept a proton and hence it is the weakest Bronsted base.

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Amines

Q 1.

Under which of the following reaction conditions, aniline gives p-nitro derivative as the major product?
(a) Acetyl chloride/pyridine followed by reaction with cone. H2SO4 + cone.
(b) Acetic anhydride/pyridine followed by cone. H2SO4 + cone. HNO3
(c) Dil. HCl followed by reaction with cone. H2SO4 + cone. HNO3
(d) Reaction with cone. HNO3 + cone. H2S04

Q 2.

Which of the following is the weakest Bronsted base?
ncert-exemplar-problems-class-12-chemistry-amines-3

Q 3.

Which of the following reactions belong to electrophilic aromatic substitution?
(a) Bromination of acetanilide
(b) Coupling reaction of aryldiazonium salts
(c) Diazotisation of aniline
(d) Acylation of aniline

Q 4.

The best reagent for converting-2-phenylpro-panamide into 1-phenylethana- mine is .
(a) excess H2/Pt (b) NaOH /Br2
(c) NaBH4/methanol (d) LiAlH4/ether

Q 5.

Which of the following should be most volatile?
ncert-exemplar-problems-class-12-chemistry-amines-26

Q 6.

Assertion (A): N, N-diethylbenzene sulphonamide is insoluble in alkalf. Reason (R): Sulphonyl group attached to nitrogen atom is strong electron withdrawing group.

Q 7.

The best reagent for converting 2-phenylpro-panamide into-2-phenyl- propanamine is .
(a) excess H2
(b) Br2 in aqueous NaOH
(c) iodine in the presence of red phosphorus
(d) LiAlH4 in ether

Q 8.

What is the role of pyridine in the acylation reaction of amines?

Q 9.

Which is the role of HNO3 in the nitrating mixture used for nitration of benzene?

Q 10.

Assertion (A): Hofmann's bromamide reaction is given by primary amines. Reason (R): Primary amines are more basic than secondary amines.

Q 11.

Arrange the following compounds in increasing order of dipole moment: CH3CH2CH3, CH3CH2NH2, CH3CH2OH.

Q 12.

Complete the following reactions:
ncert-solutions-for-class-12-chemistry-amines-37

Q 13.

A solution contains 1 g mol each of p-toluene diazonium chloride and p-nitrophenyl diazonium chloride. To this 1 g mol of alkaline solution of phenol is added. Predict the major product. Explain your answer.

Q 14.

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

Q 15.

ncert-exemplar-problems-class-12-chemistry-amines-21

Q 16.

Which of the following species are involved in the carbylamine test?
(a) R-NC (b) CHCl3 (c) COCl2 (d) NaN02 + HCl

Q 17.

The Product of the following reaction is .
ncert-exemplar-problems-class-12-chemistry-amines-32

Q 18.

The correct increasing order of basic strength for the following compounds is
ncert-exemplar-problems-class-12-chemistry-amines-13

Q 19.

In the following questions, a statement of Assertion (A) followed by a statement of Reason (R) is given. Choose the correct answer out of the following choices:
(a) Both Assertion and Reason are wrong.
(b) Both Assertion and Reason are correct but Reason is not the correct explanation of Assertion.
(c) Assertion is correct but Reason is wrong.
(d) Both Assertion and Reason are correct and Reason is the correct explanation of Assertion.
(e) Assertion is wrong but Reason is correct.

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

Q 20.

What is the product when C6H5CH2NH2 reacts with HN02?

Q 21.

Why cannot aromatic primary amines be prepared by Gabriel phthalimide synthesis?

Q 22.

Which of the following amines can be prepared by Gabriel synthesis?
(a) Isobutyl amine (b) 2-Phenylethylamine
(c) N-Methylbenzylamine (d) Aniline

Q 23.

Write down the IUPAC name of
ncert-exemplar-problems-class-12-chemistry-amines-49

Q 24.

How will you carry out the following conversion?
ncert-exemplar-problems-class-12-chemistry-amines-64

Q 25.

(i)Write the structures of different isomeric amines corresponding to the molecular formula, C4H11N.
(ii)Write 1UPAC names of all the isomers.
(iii)What type of isomerism is exhibited by different pairs of amines?

Q 26.

Why is benzene diazonium chloride not stored and is used immediately after its preparation?

Q 27.

Under what reaction conditions (acidic/basic), the coupling reaction of aryl diazonium chloride with aniline is carried out?

Q 28.

What is the structure and IUPAC name of the compound, allyl amine?

Q 29.

A compound Z with molecular formula C3H9N reacts with C6H5SO2Cl to give a solid, insoluble in alkali, identify Z.

Q 30.

Suggest a route by which the following conversion can be accomplished.
ncert-exemplar-problems-class-12-chemistry-amines-55

Q 31.

Assertion (A): Acetanilide is less basic than aniline.
Reason (R): Acetylation of aniline results in decrease of electron density on nitrogen.

Q 32.

Arrange the following in increasing order of their basic strength: ‘
(i) C2H5NH2,C6H5NH2,NH3,C6H5CH2NH2 and(C2H5)2 NH
(ii) C2H5NH2,(C2H5)2NH,(C2H5)3N,C6H5NH2
(iii) CH3NH2, (CH3)2NH, (CH3)3N, C6H5NH2, C6H5CH2NH2

Q 33.

Amongst the given set of reactants, the most appropriate for preparing 2 ° amine is .
(a) 2 ° R – Br + NH3
(b) 2 ° R – Br + NaCN followed by H2/Pt
(c) 10 R – NH2 + RCHO followed by H2/Pt
(d) 1 ° R – Br + (2 mol) + potassium phthalimide followed by H3O+/heat

Q 34.

Identify A and B in the following reaction.
ncert-exemplar-problems-class-12-chemistry-amines-57

Q 35.

Write chemical reaction of aniline with benzoyl chloride and write the name of the product obtained.

Q 36.

Predict the product of reaction of aniline with bromine in non-polar solvent such as CS2.

Q 37.

Write following conversions:
(i) nitrobenzene –> acetanilide
(ii) acetanilide –> p-nitroaniline

Q 38.

How wjll you convert:
(i) Ethanoic acid into methanamine (ii) Hexanenitrile into 1-aminopentane
(iii) Methanol to ethanoic acid. (iv) Ethanamine into methanamine
(v) Ethanoic acid into propanoic acid (vi) Methanamine into ethanamine
(vii) Nitromethane into dimethylamine (viii) Propanoic acid into ethanoic acid?

Q 39.

The correct IUPAC name for CH2 = CHCH2NHCH3 is
(a) allylmethylamine (b) 2-amino-4-pentene
(c) 4-aminopent-l-ene . (d) N-methylprop-2-en-l-amine.

Q 40.

Which of the following compounds is the weakest Bronsted base?
ncert-exemplar-problems-class-12-chemistry-amines-24

Q 41.

Arenium ion involved in the bromination of aniline is.
ncert-exemplar-problems-class-12-chemistry-amines-34

Q 42.

Explain why is MeNH2 stronger base than MeOH?

Q 43.

A primary amine, RNH2 can be reacted with CH3-X to get secondary amine, R NHCH3 but the only disadvantage is that 3 ° amine and quaternary ammonium salts are also obtained as side products. Can you suggest a method where RNH2 forms only 2 ° amine?

Q 44.

Match the compounds given in Column I with the items given in Column II.
ncert-exemplar-problems-class-12-chemistry-amines-73

Q 45.

Convert:
(i) 3-Methylanilineinto3-nitrotoluene
(ii) Aniline into 1,3,5- Tribromo benzene

Q 46.

Account for the following
(i)pKb of aniline is more than that of methylamine
(ii) Ethylamine is soluble in water whereas aniline is not.
(iii) Methylamine in water reacts with ferric chloride to precipitate hydrated ferric oxide.
(iv)Although amino group is o and p – directing in aromatic electrophilic substitution reactions, aniline on nitration gives a substantial amount of m-nitroaniline.
(v)Aniline does not undergo Friedel-Crafts reaction.
(vi)Diazonium salts of aromatic amines are more stable than those of aliphatic amines.
(vii)Gabriel phthalimide synthesis is preferred for synthesising primary amines.

Q 47.

Give the structures of A,B and C in the following reaction:
ncert-solutions-for-class-12-chemistry-amines-34
ncert-solutions-for-class-12-chemistry-amines-35

Q 48.

Which of the following is a 3 ° amine?
(a) 1 -Methylcyclohexylamine (c) tert-Butylamine

Q 49.

Among the following amines’ the strongest Bronsted base is
ncert-exemplar-problems-class-12-chemistry-amines-25

Q 50.

Which of the following cannot be prepared by Sandmeyer's reaction?
(a) Chlorobenzene (b) Bromobenzene
(c) Iodobenzene (d) Fluorobenzene