Chemistry

Amines

Question:

Explain why is MeNH2 stronger base than MeOH?

Answer:

Nitrogen is less electronegative than oxygen, therefore, lone pair of electrons on nitrogen is readily available for donation. Hence, MeNH2 is more basic than MeOH.

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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.

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

Q 5.

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

Q 6.

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

Q 8.

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

Q 9.

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

Q 10.

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

Q 11.

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

Q 12.

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 13.

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

Q 14.

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

Q 15.

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

Q 16.

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 17.

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

Q 18.

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

Q 19.

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

Q 20.

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

Q 21.

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 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.

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 24.

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

Q 25.

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

Q 26.

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 27.

Why is aniline soluble in aqueous HCl?

Q 28.

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

Q 29.

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

Q 30.

Reduction of nitrobenzene by which of the following reagents give aniline?
(a) Sn/HCl (b) Fe/HCl (c) H2-Pd (d) Sn/NH4OH

Q 31.

Explain why is MeNH2 stronger base than MeOH?

Q 32.

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

Q 33.

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

Q 34.

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

Q 35.

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

Q 36.

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

Q 37.

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 38.

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 39.

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

Q 40.

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

Q 41.

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

Q 42.

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

Q 43.

What is the product when C6H5CH2NH2 reacts with HN02?

Q 44.

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

Q 45.

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

Q 46.

(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 47.

Give plausible explanation for each of the following:
(i) Why are amines less acidic than alcohols of comparable molecular masses?
(ii) Why do primary amines have higher boiling point than tertiary amines?
(iii) Why are aliphatic amines stronger bases than aromatic amines?

Q 48.

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 49.

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

Q 50.

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