Chemistry

Amines

Question:

(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?

Answer:


ncert-solutions-for-class-12-chemistry-amines-2
Chain isomers: (a) and (c); (a) and (d); (b)and(c); (b)and(d)
Metamers: (e) and (g); (f) and (g) Functional isomers: All 10 amines are functional isomers of 2 ° and 3 ° amines and vice-versa.

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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 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 3.

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

Q 4.

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

Q 5.

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

Q 7.

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

Q 8.

Describe a method for the identification of primary, secondary and tertiary amines. Also write chemical equations of the reactions involved.

Q 9.

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

Q 10.

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

Q 11.

Why is aniline soluble in aqueous HCl?

Q 12.

How will you bring out the following conversion?
ncert-exemplar-problems-class-12-chemistry-amines-62

Q 13.

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 14.

Predict the reagent or the product in the following reaction sequence.
ncert-exemplar-problems-class-12-chemistry-amines-80

Q 15.

Write IUPAC names of the following compounds and classify them into primary, secondary and tertiary  amines.  
(i) (CH3)2 CHNH2 (ii) CH3(CH2)2NH2 (iii) CH3NHCH(CH3)2
(iv) (CH3)3 CNH2 (v) C6H5NHCH3(vi) (CH3CH2)2NCH3
(vii)m-BrC6H4NH2

Q 16.

Why is NH2 group of aniline acetylated before carrying out nitration?

Q 17.

What is the product when C6H5CH2NH2 reacts with HN02?

Q 18.

What is Hinsberg reagent?

Q 19.

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

Q 20.

Why does acetylation of -NH2 group of aniline reduce its activating effect?

Q 21.

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

Q 22.

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 23.

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 24.

What is the best reagent to convert nitrile to primary amine?

Q 25.

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

Q 26.

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

Q 27.

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

Q 28.

Which of the following reactions are correct?
ncert-exemplar-problems-class-12-chemistry-amines-37

Q 29.

Explain why is MeNH2 stronger base than MeOH?

Q 30.

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

Q 31.

Complete the following reaction.
ncert-exemplar-problems-class-12-chemistry-amines-52

Q 32.

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 33.

Assertion (A): Only a small amount of HCl is required in the reduction of nitro compounds with iron scrap and HCl in the presence of steam.
Reason (R): FeCl2 formed gets hydrolysed to release HCl during the reaction.

Q 34.

Write reactions of the final alkylation product of aniline with excess of methyl iodide in the presence of sodium carbonate solution.

Q 35.

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 36.

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

Q 37.

Match the reactions given in Column 1 with the statements given in Column II.
ncert-exemplar-problems-class-12-chemistry-amines-71

Q 38.

The reagents that can be used to convert benzene diazonium chloride to benzene are
(a) SnCl2/HCl (b) CH3CH2OH
(c) H3PO2 (d) LiAlH4

Q 39.

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

Q 40.

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

Q 41.

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

Q 42.

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

Q 43.

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

Q 44.

An aromatic compound 'A'on treatment with aqueous ammonia and heating forms compound 'B' which on heating with Br2 and KOH forms a compound 'C' of molecular formula C6H7N. Write the structures and IUPAC names of compounds A,B and C.

Q 45.

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 46.

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

Q 47.

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

Q 48.

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

Q 49.

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 50.

The most reactive amine towards dilute hydrochloric acid is
ncert-exemplar-problems-class-12-chemistry-amines-19