Tamilnadu State Board New Syllabus Samacheer Kalvi 12th Chemistry Guide Pdf Chapter 13 Organic Nitrogen Compounds Text Book Back Questions and Answers, Notes.

Tamilnadu Samacheer Kalvi 12th Chemistry Solutions Chapter 13 Organic Nitrogen Compounds

12th Chemistry Guide Organic Nitrogen Compounds Text Book Back Questions and Answers

Part – I Text Book Evaluation

I. Choose the Correct Answer

Question 1.
Which of the following reagent can be used to convert nitrobenzene to aniline
a) Sn/HCl
b) ZnHg/NaOH
c) LiAlH4
d) All of these
Answer:
a) Sn/HCl

Question 2.
The method by which aniline cannot be prepared is
a) degradation of benzamide with Br2/NaOH
b) potassium salt of phthalimide treated with chlorobenzene followed by hydrolysis with aqueous NaOH solution.
c) Hydrolysis of phenylcyanide with acidic solution.
d) reduction of nitrobenzene by Sn/HCl
Answer:
b) potassium salt of phthalimide treated with chlorobenzene followed by hydrolysis with aqueous NaOH solution.
 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds

Question 3.
Which one of the following will not undergo Hofmann bromamide reaction
a) CH3CONHCH3
b) CH3CH2CONH2
c) CH3CONH2
d) C6H5CONH2
Answer:
a) CH3CONHCH3
Solution: Only primary amides undergo Hofmann bromamide reaction

Question 4.
Assertion: Acetamide on reaction with KOH and bromine gives acetic acid
Reason: Bromine catalyses hydrolysis of acetamide.
a) if both assertion and reason are true and reason is the correct explanation of assertion
b) if both assertion and reason are true but reason is not the correct explanation of assertion.
c) assertion is true but reason is false
d) both assertion and reason are false
Answer:
d) both assertion and reason are false.

Question 5.
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 1
a) bromomethane
b) α -Bromo sodium acetate
c) methanamine
d) acetamide
Answer:
c) methanamine
Solution:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 2

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds

Question 6.
Which one of the following nitro compounds does not react with nitrous acid?
a) CH3-CH2-CH2-N02
b) (CH3)2 CH-CH2 NO2
c) (CH3)3CNO2
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 3
Answer:
c) (CH3)3CNO2
Solution:
30 Nitroalkane

Question 7.
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 4
a) Friedel – Crafts reaction
b) HVZ reaction
c) Schotten – Baumann reaction
d) None of these
Answer:
c) Schotten – Baurnann reaction

Question 8.
The product formed by the reaction of an aldehyde with a primary amine (NEET)
a) carboxylic acid
b) aromatic acid
c) Schiff’s base
d) ketone
Answer:
c) Schiff’s base

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds

Question 9.
Which of the following reaction is not correct
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 5
d) None of these
Answer:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 6
Solution:
p – nitrosation takes places, the product is im7
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 7

Question 10.
When aniline reacts with acetic anhydride the product formed is
a) o – amirìoacetophenone
b) m – aminoacetophenone
c) p – aminoacetophenone
d) acetanilide
Answer:
d) acetanilide
Solution:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 8

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds

Question 11.
The order of basic strength for methyl substituted amines in aqueous solution is
a) N(CH3)3> N(CH3)2 H > N(CH3)H2> NH3
b) N(CH3)H,> N(CH3)2H > N(CH3)3 > NH3
c) NH3> N(CH3)H2> N(CH3)2H > N(CH3)3
d) N(CH3)2 H > N(CH3)H2> N(CH3)3 > NH3
Answer:
d) N(CH3)2 H > N(CH3)H2> N(CH3)3 > NH3

Question 12.
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 9
a) H3PO2 and H2O
b) H+/H2O
c) HgSO4 / H2SO4
d) Cu2Cl2
Answer:
a) H3PO2 and H20

Question 13.
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 10
a) C6H5-OH
b) C6H5-CH2OH
c) C6H5-CHO
d) C6H5NH2
Answer:
a) C6H5-OH
Solution:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 11

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds

Question 14.
Nitrobenzene on reaction with Con HNO3 / H2SO4 at 80- 100oC forms which one of the following products?
a) 1, 4 – dinitrobenzene
b) 2, 4, 6 – tirnitrobenzene
c) 1, 2 – dinitrobenzene
d) 1, 3 – dinitrobenzene
Answer:
d) 1, 3 -dinitrobenzene
Solution:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 12

Question 15.
C5H13N reacts with HNO2 to give an optically active compound – The compound is
a) pentan-1 -amine
b) pentan-2-amine
c) N, N – dimethyipropan -2-amine
d) N-methylbutan-2-amine
Answer:
d) N-methylbutan-2-amine

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds

Question 16.
Secondary nitro alkanes react with nitrous acid to form
a) red solution
b) blue solution
c) green solution
d) yellow solution
Answer:
b) blue solution

Question 17.
Which of the following amines does not undergo acetylation?
a) t-butylamine
b) ethylamine
c) diethylamine
d) triethylamine
Answer:
d) triethylamine (3oamine)

Question 18.
Which one of the following is most basic?
a) 2, 4 – dichloroaniline
b) 2, 4 – dimethylaniline
c) 2, 4 – dinitroaniline
d) 2, 4 – dibromoaniline
Answer:
b) 2,4-dimethylaniline
Solution: CH3 is a+I group, all other – I group +T group increase the electron density on NH2 and hence increase the basis nature.

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds

Question 19.
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 13
a) Ethanol, hydroxylamine hydrochloride
b) Ethanol, ammonium hydroxide
c) Ethanol, NH2OH
d) C3H5NH2, H2O
Answer:
a) Ethanol, hydroxylamine hydrochloride

Question 20.
UPAC name for the amine
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 14
a) 3 – Bimethy lamino – 3 – methyl pentane
b) 3(N,N – Triethyl) – 3 – amino pentane
c) 3-N,N – trimethyl pentanamine
d) 3 – (N,N – Dimethyl amino) – 3- methyl pentane
Answer:
d) 3 – (N,N – Dimethyl amino) -3- methyl pentane

Question 21.
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 15
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 16
Answer:
b)Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 17

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds

Question 22.
Ammonium salt of benzoic acid is heated strongly with P2O5 and the product so formed is reduced and then treated with NaNO2/ HCl at low temperature. The final compound formed is
a) Benzene diazonium chloride
b) BenzYl alcohol
c) Phenol
d) Nitrosobenzene
Answer:
b) Benzyl alcohol
Solution:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 18

Question 23.
Identify X in the sequence given below.
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 19
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 20
Answer:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 21

Question 24.
Among the following, the reaction that proceeds through an electrophilic substitution, is:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 22
Answer:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 23
Explanation:
a) Nucleophilic substitution
b) Electrophilic substitution
c) Addition Reaction
d) Nucleophilic substitution

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds

Question 25.
The major product of the following reaction
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 24
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 25
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 26
Answer:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 27
Solution:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 28

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds

II. Short Answer Questions

Question 1.
Write down the possible isomers of the C4H9NO2 and give their IUPAC names
Answer:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 29
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 30
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 31

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds
Question 2.
There are two isomers with the formula CH3 NO2. How will you distinguish between them?
Answer:

  • Primary and secondary nitroalkanes with a-H atom exhibit tautomerism.
  • Tertiary amines do not exhibit tautomerism due to CH =N the absence of a-H atom.
  • Nitromethane exists in two tautomeric forms namely \itro form Aci form nitroform and aciform.

Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 32

Nitro Form Aci – Form
1. Less Acidic More acidic and also called pseudoacids (or) nitronic acids.
2. Dissolves in NaOH slowly Dissolves in NaOH instantly.
3. Decoiourises FeCl3 Solution With FeCl3, gives reddish-brown colour
4. Electrical conductivity is low Electrical conductivity is high

Question 3.
What happens when
Answer:
i) 2 – Nitropropane boiled with HCl
ii). Nitrobenzene electrolytic reduction in strongly acidic medium.
iii). Oxidation of tert – butylamine with KMnO4
iv). Oxidation of acetone oxime with trifluoromethoxy acetic acid.
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 33
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 34
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 35

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds

Question 4.
How will you convert nitrobenzene into
Answer:

  • 1, 3, 5 – trinitrobenzene
  • o and p – nitrophenol
  • m – nitro aniline
  • azoxvbenzcne
  • hvdrazohenzene
  • N – phenvl hyd roxylamine
  • aniline

Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 36
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 37

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds
Question 5.
Identify compounds A, B, and C in the following sequence of reactions.
Answer:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 38
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 39
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 40
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 41
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 42
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 43
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 44

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds
Question 6.
Write short notes on the following
Answer:

  • Hofmann’s bromide reaction
  • Ammonolysis
  • Gabriel phthalimide synthesis
  • Schotten – Baurnann reaction
  • Carhvlamine reaction
  • Mustard oil reaction
  • Coupling reaction
  • Diazotisation
  • Gorenberg reaction

I Hofmann’s bromamide reaction:

Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 45
In Hofnianns degradation acid amide is converted into an amine with one carbon less by Br2/ KOH.

ii. Ammonolysis:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 46
In Hoffmann’s ammonolysis alkyl halides are heated with alcoholic ammonia in a sealed tube, mixtures of 1o, 2o and 3o amines and quarternary ammonium salts are obtained.

iii. Gabriel phthalimide synthesis
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 47
Phthalimide on treatment with alcoholic KOH forms potassium phthalimide which on heating with alkyl halide followed by alkaline hydrolysis gives primary amine. Aniline can not be prepared by this method.

iv. Schotten – Baumann reaction:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 48
Benzoylation of amines to give N-alkyl benzamide in presence of NaOH is known as Schotten Baumann reaction.

v. Carbylamine reaction
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 49
Primary’ amines react with chloroform and alcoholic KOH to form isocyanides called carbylamines with unpleasant smell. This is used to identify primary amines.

vi. Mustard oil reaction
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 50When primary amines are treated with carbon disulphide, N-alkyl dithiocarbamic acid is formed which on treatment with HgCl2 gives an alkyl isothiocyanate.

vii. Coupling reaction:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 51
Benzenediazonium chloride reacts with electron-rich aromatic compounds like phenol, undergoing
electrophilic substitution at para position.

viii. Diazotisation:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 52
Aniline reacts with nitrous acid at 273-278K to form benzene diazonium chloride.

ix. Gomberg reaction:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 53
Benienediazonium chloride reacts with benzene in presence of NaOH to give biphenyl.
 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds

Question 7.
How will you distinguish between Primary, Secondary, and tertiary aliphatic amines
Answer:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 54
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 55

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds
Question 8.
Account for the following
Answer:

  • Aniline does not undergo Friedel – Crafts reaction
  • Diazonium salts of aromatic amines are more stable than those of aliphatic amines.
  • pKb of aniline is more than that of methylamine
  • Gabriel phthalimide synthesis is preferred for synthesising_primary amines
  • Ethvlamine is soluble in water whereas aniline is not
  • Amines are more basic than amides
  • Although amino group is o – and p – directing in aromatic electrophilic substitution reactions, aniline on nitration gives a substantial amount of m – nitroaniline.

i) Aniline does not undergo Friedel – crafts reaction, because Aniline is basic in nature
Aniline donates its lone pair to the lewis acid Alcl3 to form an adduct which inhibits further electrophilic substitution reaction

ii) The stability of diazonium salts of aromatic amines is due to the dispersal of the positive charge over the benzene ring.
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 56

iii) In aniline the NH
group is directly attached to the benzene ring.
The lone pair of electron on nitrogen atom in aniline gets delocalised over the benzene ring.
Hence it is less available for protonation.
So aniline is less basic than methylamine and pKb of aniline is more than that of methylamine.

iv) Gabriel phthalimide synthesis results in the formation of primary amines only. Secondary and tertiary amines are not formed in this synthesis. Thus a pure primary amine can be obtained.
Therefore, Gabriel phthalimide synthesis is preferred for synthesizing primary amines.

v) Ethvlamine forms intermolecular hydrogen bonds with water. Hence it is soluble in water.
But aniline does not form hydrogen bond with water to a very large extent due to the presence of a large hydrophobic C6H5 – group. Hence aniline is insoluble in water

vi) In amides the carbonyl group (C = 0) is highly electronegative and draws the electrons towards it.
This makes the lone pair of amide nitrogen less available to accept a proton.
Hence amides are less basic than amines.
But in amines the alkyl groups being electron releasing groups. the electron pair on amine nitrogen is readily available to accept a proton.

vii) Hence amines are more basic than amides.
In strong acid medium aniline is protonated to form anilinium ion which is rn-directing.
Hence a substantial amount of rn-nitroaniline is formed during nitration of aniline.

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds

Question 9.
Arrange the following
Answer:
i) In increasing order of solubility in water C6H5NH2,(C2H5)2NH,C2H5NH2
ii) In increasing order of basic strength
a) aniline, p – toludine and p – nitroaniline
b) C6H5NH2 C6H5NHCH3, C6H5NH2, p-Cl-C6H4-NH2
iii) In decreasing order of basic strength in gas phase
(C2H5)NH2, (C2H5)NH, (C2H5)3N and NH3
iv) In increasing order of boiling point C6H5OH, (CH3)2NH,C2H5NH2
v) In decreasing order of the pKb values C2H5NH2, C6H5NHCH3, (C2H5)2NH and CH3NH2
vi) Increasing order of basic strength C6H5NH2, C6H5N(CH3) H53)2, (C2H5)2 NH and CH3 NH2
vii) In decreasing order of basic strength
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 153

i) Increasing order of solubility in water C6H5NH2 < (C2H5) NH < C2H5 NH2
Hint
Aromatic amine
aliphatic amine
Solubility α \(\frac{1}{\text { Molarmass }}\)
ii) Increasing order of basic strength
a) p-nitro aniline
aniline
p-toludine
b) p – Cl- C6H4– NH2 < C6H5NH2 < C6H5NHCH3 < C6H5NH2
Hint > p-nitrogroup (-I) electron with drawing, hence decreases the basic strength.
Hint > p-methyl group (+I) electron releasing, hence increases the basic strength.
iii) Decreasing order of basic strength in gas phase
(C2H5)3N > (C2H5)2 NH > C2H5 NH2> NH3
Hint > In the gas-phase there is no solvation effect. As a result the basic strength mainly depends on the + I effect. Higher the number of alkyl groups higher will be the +1 effect, stronger is the base.
iv) Increasing order of boiling point.
(CH3)2NH <C2H5NH2 <C6H5OH
Hint > Amines generally have lower boiling point than alcohols of comparable molar mass. Since amines have weaker H-bonds.
Hint
Secondary amines
primary amines
v) Decreasing order of pK values
C6H5NHCH3> C2H5NH2> CH3 NH2> (C2H5)2 NH
Hint > Basic character increases. pKb value decreases. Higher the basic nature, lower will be the pkb’ value.
vi) Increasing order of basic strength
C6H5NH2 < C6H5-N(CH3)2 < CH3 NH2 < (C2H5)2NH
vii) Decreasing order of basic strength

Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 58

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds
Question 10.
How will you prepare propan – 1 – amine from
Answer:
i) butane nitrile
ii) propanamide
iii) 1-nitropropane
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 59

Question 11.
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 60
Answer:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 61

Compound Name
A Methanamirie
B N – ethyl N – methyL ethanamine
C Diethyl methyl ammonium hydrogen sulphate

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds
Question 12.
How will you convert diethylamine into
Answer:
i) N,N – dimethylacetamide
ii) N – nitrosódiethylamine
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 62

Question 13.
Identify A, B and C
Answer:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 63

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds
Question 14.
Identify A,B,C and D
Answer:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 64

Question 15.
Complete the following reaction
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 65
Answer:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 66

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds
Question 16.
Predict A,B, C and D for the following reaction
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 67
Answer:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 68
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 69

Compound Name
A Phthaliniide
B Isopropyl bromide
C N-isopropy1ththalimide
D Phthalic acid

Question 17.
A dibromo derivative (A) on treatment with KCN followed by acid hydrolysis and heating gives a monobasic acid (B) along with liberation of CO2 . (B) on heating with liquid ammonia followed by treating with Br2 / KOH gives (c) which on treating with NaNO2 and HC1 at low temperature followed by oxidation gives a monobasic acid (D) having molecular mass 74. Identify A to D.
Answer:
D is a monobasic and with molecular mass 74.
M.F of D is CnH2n+1COOH
MolarMassis 12 × n + 2n × 1 + 1 × 1 + 12 + 2 × 16 + 1 × 1 = 74
14n + 46 = 74
14n=28
n=2
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 70
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 71

Compound Name
A 1, 1- dibromopropane
B Butanoic acid
C 1 – amino propane
D Propanoic acid

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds
Question 18.
Identify A to E in the following frequency of reactions
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 72
Answer:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 73

Compound Name
A o – nitro toluene
B o – amino toluene
C o – amino toluene
D o – methyl benzene diazonium chloride
E o – cyano toluene

III. Evaluate Yourself

Question 1.
Write all possible isomers for the following compounds.
Answer:
i) C 2H 5 – NO 2
ii) C 3H 7 – NO 2
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 74
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 75

Question 2.
Find out the product of the following reactions.
Answer:

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds
Question 3.
Predict the major product that would be obtained on nitration of the following compounds?
Answer:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 77
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 78

Question 4.
Draw the structure of the following compounds
i. Neopentylaniine
ii. Tert – butylamine
iii. α- amino propionaldehyde
iv. Tribenzylamine
v. N – ethyl – N – methyihexan – 3- amine
Answer:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 79

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds
Question 5.
Give the correct IUPAC names for the following amines
Answer:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 80

12th Chemistry Guide Organic Nitrogen Compounds Additional Questions and Answers

Part – II – Additional Questions

I. Choose the correct answer

Question 1.
Nitro ethane and ethyl nitrite are
a) chain isomers
b) position isomers
c) functional isomers
d) tautomers
Answer:
c) functional isomers

Question 2.
1-nitrobutane and 2-nitrobutane are
a) chain isomers
b) Position isomers
c) functional isomers
d) tautomers
Answer:
b) Position isomers

Question 3.
1-nitrobutane and 2- methyl-1-nitro propane are
a) chain isomers
b) Position isomers
c) funtional isomers
d) tautomers
Answer:
a) chain isomers

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds

Question 4.
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 81
a) chain isomers
b) position isomers
c) functional isomers
d) tautorners
Answer:
d) tautomers

Question 5.
Which among the following is a tertiai nitroalkane?
a) 2-nitro propane
b) 2-methyl-.1—nitro propane
C) 2-methyl – 2-nitropropane
d) nitro ethane
Answer:
c) 2-methyl – 2-nitropropan

Question 6.
Which among the following does not sho tautomerism?
a) 2-nitro propane
b) 2-methyl-1-nitropropane
c) 2-methyl-2-nitropropane
d) nitro ethane
Answer:
c) 2-methyl-2-nitropropane
Hint : Tertiary Nitroalkanes do not exhibit tautomerism due to the absence of Oc-H atom.

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds

Question 7.
Which nitro alkane does not dissolve in NaOH?
a) 2-nitro propane
b) 2-methyl – 1 – nitro propane
c) 2 – methvl-2-nitropropane
d) nitroethane
Answer:
c) 2 – methyl- 2 – nitropropane
Hint : Tertiary mitroalkanes do not react with NaOH due to the absence of ∝-H atom.

Question 8.
Which among the following does not react with Nitrous acid.
a) 2 – nitro propane
h) 2-methyl-1-nitropropane
c) 2 – methyl – 2 – nitro propane
d) nitro ethane
Answer:
c) 2 – methyl – 2 – nitro propane
Hint : Tertiary mitroalkanes do not react with nitrous acid due to the absence of ∝- H atom.

Question 9.
The correct order of acidic nature of nitro alkanes is
a) nitro propane> nitroethane > nitro methane
b) nitro propane c) nitro methane < nitro ethane < nitro propane d) nitro ethane> nitro methane> nitro propane
Answer:
b) nitro propane < nitroethane < nitromethane
Hint: Length of alkyl group attached to the ∝- carbon increases, acidic nature decreases

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds

Question 10.
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 82
The above reaction follows the mechanism
a) E1
b) E2
c) SN1
d) SN2
Answer:
d) SN2

Question 11.
Acetaldoxime is converted into nitroethane by reaction with
a) HNO2
b) CF3COOOH
c) KMnO4
d) HNO3/H2SO4
Answer:
b) CF3COOOH

Question 12.
Oil of mirbane is
a) nitro ethane
b) nitro propane
c) nitro benzene
d) nitro aniline
Answer:
c) nitrobenzene

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds

Question 13.
Direct nitration of nitro benzene gives
a) o – dinitro benzene
b) m – dinitro benzene
c) p – dinitro benzene
d) All the above
Answer:
b) m – dinitro benzerte

Question 14.
P – diamino benzene can be converted to p – dinitro benzene by
a) Caros acid
b) persuiphuric acid
c) peroxy trifluoro acetic acid
d) all the above
Answer:
d) all the above

Question 15.
Nef carbonyl synthesis given by
a) C6H5CHO
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 83
c) C6H5CH2NO2
d) All of these
Answer:
a) C6H5CHO

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds

Question 16.
In electrophilic substititution reaction of nitro benzene, the – NO2 group acts as
a) activating group and m – directing
b) deactivating group and rn-directing
c) activating group and o,p – directing
d) deactivating group and o,p -directing
Answer:
b) deactivating group and m-directing

Question 17.
Identify X in the following sequence of reaction
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 84
a) (CH3)2CHCOCl
b) CH3CH2CH(OH)CH2Cl
c) CH3CH2CH2COCl
d) ClCH2CH2CH2CHO
Answer:
c) CH3CH2CH2COCl

Question 18.
The reducing agent used to reduce alkylcyanides to primary amines is
a)H2/Ni
b)LiAlH4
c) Na/C2H5OH
d) all the above
Answer:
d) all the above

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds

Question 19.
The reducing agent used in Mendius reaction is
a) H2/Ni
b) LiAlH4
c) Na/C2H5OH
d) NaBH4
Answer:
c) Na/C2H5OH

Question 20.
Reduction of alkyl iso cyanides give
a) primary amines
b) secondary amines
c) tertiary amines
d) none of the above
Answer:
b)secondary amines

Question 21.
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 85
a) CH3NH2, CH3CH2NH2
b) CH3OH, CH2CH2OH
c) CH3CH2NH2, CH3NH2
d) CH3CN, CH3CH2CN
Answer:
c) CH3CH2NH2, CH3NH2

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds

Question 22.
Gabriel phthalimide synthesis is used for the preparation of
a) aliphatic primary amines
b) aromatic primary amines
c) both (a) & (b)
d) none of the above
Answer:
a)aliphatic primary amines

Question 23.
Which among the following can not be prepared by Gabriel phthalimide synthesis?
a) Methanamine
b) ethanamine
c) benzenamine
d) propananiine
Answer:
c)benzenamine

Question 24.
Two molecules of propannitrile in the presence of Na/Ether to form 3-imino- 2-methylpentanenitrile. This reaction is known as
a) Baltz – schiemann reaction
b) Thorpe nitrile condensation
c) Gomberg reaction
d) hotten – Baurnann reaction
Answer:
b) Thorpe nitrile condensation

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds

Question 25.
In Hoffmann’s ammonolysis, if excess alkyl halide is taken, the final product is
a) primary amine
b) secondary amine
c) tertiary amine
d) quaternary ammonium salt
Answer:
d) quaternary ammonium salt

Question 26.
Hoffmann’s ammonolysis reaction is an example of
a) nucleophilic addition
b) nucleophilic substitution
c) electrophilic addition
d) electrophilic substitution
Answer:
b) nucleophilic substitution

Question 27.
In Hoffmann’s ammonolysis the order of reactivity of alkyihalides with amines is
a) RI > RBr> RCl
b) RI < RBr < RCl c) RI > RBr < RCl
d) RI < RBr> RCl
Answer:
a)RI>RBr>RCl

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds

Question 28.
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 86
A and B are respectively
a) CH3Na, CH3CN
b) CH3NH2,CH3N3
c) CH3N3 CH3NH2
d) CH3NH2,CH3CN
Answer:
c) CH3N3 CH3NH2

Question 29.
The correct ascending order of basic strength of alkylamines in aqueous solution is.
a) R2NH > RNH2 > R3N > NH3
b) NH3 > R3N > RNH2 > R2NH
c) NH3 < R3N < RNH2 < R2NH
d) R2NH < RNH2 < R3N < NH3
Answer:
c) NH3 < R3N < RNH2 < R2NH

Question 30.
Among the three types of amines, secondary amine is more basic due to
a) +1 effect
b) steric effect
c) hydration effect
d) all the above
Answer:
d) all the above

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds

Question 31.
In case of sustituted aniline, the groups which increase the basic strength are
(i) -CH3
(ii) -NO2
(iii) -OCH3
(iv) -Cl
a) (i) & (ii)
b) (i) & (iii)
c) (ii) & (iii)
d) (iii) & (iv)
Answer:
b)(i) & (iii)

Question 32.
The correct order of basic strength of amines is
a) C6 H5 – NH2 > C6 H5 CH2 NH2> NH3 > C6 H5 CH2 NHCH3 > C2 H5 NH2

b) C6 H5 CH2 NH2 > C6 H5 CH2 NHCH3 > NH3 > C6 H5 NH2 > C2H5NH2

c) C2 H5 NH2 > C6H5 CH2 NH2 > NH3 > C6 H5 CH2 NHCH3 > C6 H5 NH2

d) C6 H5CH2 NH CH3 > C6 H5 CH2 NH2 > NH3 > C2 H5 NH2 > C6 H5 NH2
Answer:
c) C2 H5 NH2 > C6H5 CH2 NH2 > NH3 > C6 H5 CH2 NHCH3 > C6 H5 NH2
Hint : Alkylamine > Aralkvlamine > Ammonia > N – Aralkylamine > Arylamine

Question 33.
Schotten Baumann reaction is an example of
a) nucleophilic substitution
b) nucleophilic addition
c) electrophilic substitution
d) electropholic addition
Answer:
a)nucleophilic substitution

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds

Question 34.
The product ‘D’ of the reaction
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 87
a) CH3CH2NH2
b) CH3CN
c) HCONH2
d) CH3CONH2
Answer:
d) CH3CONH2

Question 35.
The test used to identify a primary amine is
a) iodoform test
b) silver mirror test
c) libermann’s nitroso test
d) carbylamine test
Answer:
d) carbylamine test

Question 36.
The test used to identify a secondary amine is
a) iodo form test
b) silver mirror test
c) Libermann’s nitroso test
d) carbylamine test
Answer:
c) Libermann’s nitroso test

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds

Question 37.
When ethylamine is treated with chloroform and alcoholic KOH an unpleasant smell is evolved due to the formation of
a) ethylcyanide
b) ethylisocyanide
c) ethylisocyanate
d) ethylcyanate
Answer:
b) ethylisocyanide

Question 38.
C6H5N + 2Cl + H3PO2 + H2O → C6H6 + H3PO3 + HCl + N2 This reaction proceeds through
a) SN1 mechanism
b) SN2 mechanism
c) free radical mechanism
d) elimination reaction
Answer:
c) free radical mechanism

Question 39.
Benzene diazonium chloride is converted into chloro benzene by
(i) Sandmeyer reaction
(ii) Gatter mann reaction
(iii) Gomberg reaction
a) (i) &(ii)
b) (i.) & (iii)
c) (ii) & (iii)
d) (i) (ii) & (iii)
Answer:
a)(i) &(ii)

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds

Question 40.
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 88
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 89
Answer:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 90

Question 41.
Hydrogen cyanide and hydrogen isocyanide are
a) chain isomers
b) position isomers
c) tautomers
d) Geometrical isomers
Answer:
c) tautomers

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds

Question 42.
The IUPAC name of C6H5CN is
a) phenyl cyanide
b) benzene carbonitrile
c) benzonitrile
d) benzene cyanide
Answer:
b) benzene carbonitrile

Question 43.
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 91
a) CH3CN
b) CH3NH2
c) CH3CONH2
d) CH3CH2CONH2
Answer:
d) CH3CH2CONH2

Question 44.
Methyl magnesium chloride is converted into ethanenitrile by treating with
a) cyanogen
b) cyanogen chloride
c) methyl cyanide
d) hydrogen cyanide
Answer:
b) cyanogen chloride

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds

Question 45.
Which one of the following compound is a strong base?
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 92
Answer:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 93

Question 46.
Which among the following will not undergo diazotisation?
a) m- toluidine
b) aniline
c) p – amino phenol
d) benzylamine
Answer:
d) benzylamine
Hint: Aromatic amines in which – NH2 group is directly attached to the benzene ring undergo diazotisation

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds

Question 47.
An organic compound (A) C3H9N when treated with nitrous acid, gave an alcohol (B) and N2 gas. (A) on warming with CHCl3 and Caustic potash gave (C) which on reduction gave isopropyl methylamine. Organic compound (A) is
a) CH3CH2NH CH3
b) CH3 CH2 CH2 NH2
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 94
Answer:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 95
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 96

Question 48.
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 97
a) Ethanamide, Ethanamine, Ethanol
b) Ethanarnine, Ethanol, Ethanoic acid
c) Ethanol, Ethanal, Ethanoic acid
d) Ethanamine, Ethanal, Ethanoic acid
Answer:
b) Ethanamine, Ethanol, Ethanoic acid
Hints:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 98

Question 49.
Which of the following nitro compounds when reacted with nitrous acid followed by treatment with alkali produces blue colour?
a) 2-methyl-2-nitropropane
b) 2-methyl-1-nitropropane
c) 2-nitropropane
d) nitrobezene
Answer:
c) 2-nitropropane
Hunt: Nitro group attached to a secondary carbon atom will give pseudonitrol with HNO2 which on further reaction with alkali gives blue colour.
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 99

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds
II. Assertion and reason

Question 1.
Assertion (A) : Aniline when exposed to air becomes coloured
Reason (R) : Aniline when exposed to air undergoes oxidation
a) Both A and R are correct, R explains A
b) Both A and R are correct, R does not explain A
c) A is correct but R is wrong
d) A is wrong but R is correct
Answer:
a) Both A and R are correct, R explians A

Question 2.
Assertion (A) : Aniline is more basic than ammonia
Reason (R) : The lone pair of electron on nitrogen atom in aniline gets delocalised over the benzene ring.
a) Both A and R are correct, R explains A
b) Both A and R are correct, R does not explain A
c) A is correct but R is wrong
d) A is wrong but R is correct
Answer:
d) A is wrong but R is correct.
Correct Assertion A: Aniline is less basic than ammonia.

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds

Question 3.
Assertion (A) : Nitroalkanes are more acidic than aldehvdes, ketones and cyanides.
Reason (R) : a-H atom of 10 and 20 nitroalkanes, show acidic character because of the electron releasing effect of NO2 group.
a) Both A and R are correct, R explains A
b) Both A and R are correct, R does not explain A
c) A is correct but R is wrong
d) A is wrong but R is correct
Answer:
c) A is correct but R is wrong.
Correct Reason (R) : a- H atom of 1o and 2o nitroalkanes show acidic character because of the electron withdrawing effect of NO2 group.

Question 4.
Assertion (A) : Nitro benzene does not undergo Friedel crafts reactions:
Reason (R) : NO2 group present in the benzene ring is strongly deactivating in nature.
a) Both A and R are correct, R explains A
b) Both A and R are correct, R does not explain A
c) A is correct but R is wrong
d) A is wrong but R is correct
Answer:
a) Both(A) and (R) are correct, R explains A.

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds

III. Pick out the correct statement

Question 1.
(i) In amines the nitrogen atom is Sp3 hybridised.
(ii) In amines, the fourth Sp3 hybridised orbital contains a lone pair of electron.
(iii) Due to the presence of lone pair of electron C- N-C bond angle is more than the normal tetrehedral bond angle.
(iv) The C-N-C bond angle of trimethylamine is 1090 which is greater than tetrahedral angle,
(a) (i) & (ii)
(b) (ii)&(iii)
(c) (iii)&(iv)
(d) (I&(iv)
Answer:
(a)(i) & (ii)
Correct statement:
(iii) Due to the presence of lonepair of electron C-N-C bond angle is less than the normal tetrahedral bond angle.
(iv) The C-N-C bond angle of trimethylamine is 1080 which is lower than tetrahedral angle.

Question 2.
(i) Tertiary amines form inter molecular hydrogen bond.
(ii) Amines have higher boiling points than alcohols.
(iii) Nitrogen being less electronegative than oxygen, the N-H bond in amines is less polar than O-H bond in alcohols
(iv) Lower aliphatic amines are soluble in water, since they form hydrogen bond with water,
(a) (i) & (ii)
(b) (ii) & (iii)
(c) (iii) & (iv)
(d) (i) & (iv)
Answer:
(c) (iii) & (iv)
Correct Statement:
(i) Tertiary amines do not form intermolecular hydrogen bond.
(ii) Amines have lower boiling point than alcohols.

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds

Question 3.
(i) In Hofmann’s degradation reaction primary amines with one carbon less than the parent amides are formed.
(ii) Gabriel phthalimide synthesis is useful for the preparation of three types of amines.
(iii) Alkyl halides can be converted to primary amines by treating with sodium azide followed by reduction using LiAlH4
(iv) When phenol reacts with ammonia in presence of anhydrous ZnCl2 gives p -amino phenol.
a) (i) & (ii)
b) (ii) & (iii)
c) (i) & (iii)
d) (i) & (iv)
Answer:
c)(i) & (iii)
Correct statement:
(ii) Gabriel phthalimide synthesis is useful for the preparation of aliphatic primary amines
(iv) When phenol reacts with ammonia in presence of anhydrous ZnCl2 gives aniline.

Question 4.
(i) Alkyl cyanides on reduction with LiAlH4 give secondary amines.
(ii) Alkyl cyanides on hydrolysis with alkali or dilute mineral acid give carboxylic acids.
(iii) Nitriles containing a- H atom undergo condensation with esters in presence of sodamide in ether to form ketonitriles.
(iv) Alkycyanides have lower boiling points than analogous acetylenes
a) (i) & (ii)
b) (ii) & (iii)
c) (i) & (iii)
d (i) & (iv)
Answer:
b)(ii) & (iii)
Correct statement:
(i) Alkylcyanides on reduction with LiAlH4 give primary amines.
(iv) Alkylcyanides have higher boiling points than analogous acetylenes.

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds

IV. Pick out the incorrect statement

Question 1.
(i) Bromobenzene can be converted into nitrobenzene by reacting with KNO2
(ii) Nitroethane is suspected to cause genetic damage and be harmful to the nervous system.
(iii) 2-methyl – 2-nitro propane reacts with HCl undergoing hydrolysis to form 2-methyl – 2 – propanol.
(iv) Ethyl nitrite on reduction with Sn / HCl gives ethanol.
a) (i) & (ii)
b) (ii) & (iii)
c) (i) & (iii)
d) (iii) & (iv)
Answer:
c) (i) & (iii)
Correct statement:
(i) Bromo benzene can not be converted into nitrobenzene by reacting with KNO2
(iii) 2-methyl -2-nitropropane does not undergo hydrolysis with HCl to form 2-methyl – 2 – propanol

Question 2.
(i) Nitroalkanes exhibit functional isomerism with alkyl nitrites.
(ii) Tertiary nitroalkanes exhibit tautomerism due to the absence of a-H atom.
(iii) The electrical conductivity of aciform of nitro alkanes is high.
(iv) When the number of alkyl group attached to the a- carbon of nitroalkane increases, its acidity increases.
a) (i) & (ii)
b) (ii) & (iii)
c) (ii) & (iv)
d) (i) & (iv)
Answer:
c) (ii) & (iv)
Correct statemet:
(ii) Tertiary nitroalkanes do not exhibit tautomerism due to the absence of a- H atom.
(iv) When the number of alkyl group attached to the a- carbon of nitro alkane increases its acidity decreases.

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds

Question 3.
(i) Benzoylation of aniline is known as Schotten. Baumann reaction
(ii) The reaction of ethylamine with nitrous acid is known as diazotisation.
(iii) The reaction of primary amine with nitrous acid is known as Libermann’s nitroso test.
(iv) The reaction of primary amine with CS2 and HgCl2 is known as Mustard oil reaction.
a) (i) & (ii)
b) (ii) & (iii)
c) (ii) & (iv)
d) (i) & (iv)
Answer:
b) (ii) & (iii)
Correct statement:
(ii) The reaction of aniline with nitrous acid is known as diazotisation.
(iii) The reaction of secondary amine with nitrous acid is known as Libermann’s nitroso test.

Question 4.
(i) Diazo compounds obtained from the coupling reactions of diazonium salts are coloured and are used as dyes.
(ii) Aryl fluorides and iodides can not be prepared by direct halogenation but can be prepared by using benzene diozonium chloride.
(iii) In Sandmeyer reaction and Gattermann reaction the catalyst used are Cu/HCl and Cu2Cl2 / HCZ respectively .
(iv) Benzene diazonium chloride when added with boiling water gives benzene.
a) (i) & (ii)
b) (ii) & (iii)
c) (iii) & (iv)
d) (i) & (iv)
Answer:
c) (iii) & (iv)
Correct statement:
(iii) In Sandmeyer reaction and Gattermann reaction the catalyst used are Cu2Cl2/ HCl and Cu / HCl respectively
(iv) Benzene diazonium chloride when added with boiling water gives phenol.

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds

V. Match the following

Question 1.

Reducing agent Reduced product of nitrobenzene
1. Zn / NH4Cl Hydrazobenzene
2. SnCl2 / KOH Aniline
3. Sn /HCl Nitrosobenzene
4. Zn / NaOH Phenylhydroxylamine
5. Fe / steam Azobenzene

Answers:
1. – Phenylhydroxylamine
2. – Azobenzene
3. – Aniline
4. – Hydrazo benzene
5. – Nitrosobenzene

Question 2.
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 100
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 101
Answer:
1. – Prop – 2-en-1-amine
2. – N – methylpropan – 2 – amine
3. – Hexan -1, 6 – diamine
4. – Phenylmethanamine
5. – N, N – dimethylben zenamine

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds
Question 3.

Reaction Product
1. Schotten Baumann reaction Methyl isothiocyanate
2. Diazotistation P-hvdroxy azobenzene
3. Carbylamine test N – phenylbenzamide
4. Mustard oil reaction Benzene diazonium chloride
5. Coupling reaction Methylisocyanide

Answer:
1. – N-phenylbenzamide
2. – Benzene diazonium chloride
3. – Methyl isocyanide
4. – Methylisothiocyanate
5. – p-hydroxyazobenzene

Question 4.

Compound Use
Chloropicrin Fuel additive
Ethyl nitrite Solvent in perfume industry
Nitrobenzene diuretic
Nitro ethane TNT
Nitriles insecticide

Answer:
1. – insecticide
2. – diuretic
3. – TNT
4. – fuel additive
5. – Solvent in perfume industry

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds

VI. Two Mark Questions

Question 1.
Write a note on acidic nature of nitroalkanes.
Answer:

  • α-H atom of 10and 20nitroalkanes show acidic character.
  • This is due to the electron withdrawing effect of – NO2group.
  • Nitroalkanes are more acidic than aldehydes, Ketones, esters and cyanides.
  • Due to acidic nature nitroalkanes dissolve in NaOH to form a salt.
  • Aci-nitro form is more acidic than nitro form.
  • As the number of alkyl group attached to a- Carbon increases, acidity decreases due to + I effect of alkyl groups.

Question 2.
How is the oil of mirbane prepared?
Answer:
When benzene is heated at 330K with the nitrating mixture (Con HNO3 + Con H2S04), electrophilic substitution takes place to form nitrobenzene (oil of mirbane)
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 102

Question 3.
How is P – dinitrobenzene prepared?
Answer:

  • Direct nitration is nitrobenzene gives m-dinitro benzene.
  • The following indirect method is adopted to prepare p-dinitrobenzene.
    Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 103

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds
Question 4.
Convert p-diamino benzene into p-dinitro benzene.
Answer:
Amino group can be directly converted into nitro group using Caro’s acid (H2SO5) or persulphuric acid (H2S2O8) or peroxytrifluro acetic acid (CF3COOOH) as oxidising agent
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 104

Question 5.
Write the various reduction stages of nitromethane.
Answer:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 105

Question 6.
Write about the reduction of nitro methane in acid medium and neutral medium.
Answer:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 106

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds
Question 7.
What happpens when ethylnitrite is reduced by Sn / Hcl?
Answer:

  • Ethyl nitrite on reduction with Sn / HCl gives ethanol.

Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 107

Question 8.
What happens when ethyl nitrite undergoes hydrolysis with acid or base?
Answer:

  • Ethyl nitrite undergoes hydrolysis with acid or base to give ethanol.

Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 108

Question 9.
What is Nef Carbonyl Synthesis?
Answer:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 109

Question 10.
Write about the electrolytic reduction of nitro benzene?
Answer:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 110

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds
Question 11.
Convert m- dinitrobenzene into m – nitroaniline
Answer:
Selective reduction of rn – dinitrobenzene with ammonium suiphide gives m – nitroaniline
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 111

Question 12.
What happens when
(i) methyl cyanide and
(ii) methyl isocyanide are reduced?
Answer:
(i) Methyl cyanide on reduction gives a primary amine ethanamine.
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 112
(ii) Methylisocyanide on reduction gives a secondary amine N-methylmcthanamine
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 113

Question 13.
How can you convert acetamide into
(i) ethanamine
(ii) methanamine.
Answer:
Acetamide on reduction with LiAlH4 gives ethanamine.
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 114

Acetamide undergoes Hofmanns degradation with Br2/KOH to form methanamine
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 115

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds
Question 14.
Write about Sabatier – Mailhe method of preparing three types of Amines
Answer:

  • Vapour of an alcohol and ammonia are passed over alumina, W2O5 or Silica as 400o Call the types of amines are formed.
  • This method is known as Sabatier-Mailhe method.

Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 116

Question 15.
Write a note on basic strength of aniline.
Answer:

  • Aniline is less basic than alkylamines and ammonia.
  • In aniline, the NH2 group is directly attached to the benzene ring.
  • The lone pair of electron in nitrogen atom in aniline gets delocalised over the benzene ring.
  • Hence it is less available for protonation.
  • In case of subtituted aniline, election releasing groups like – CH3, -OCH3, -NH2 increase the basic strength.
  • Electron with drawing groups like -NO2, -X, -COOH decrease the basic strength.

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds
Question 16.
How is sulphanilic acid prepared?
Answer:

  • Aniline reacts with conc H2SO4to form anilinium hydrogen sulphate.
  • This on heating with H2SO4 at 453-473K gives p-aminobenzene suiphonic acid known as
    sulphanilic acid

Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 107 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 117

Question 17.
How will you convert aliphatic carboxylic acid into aromatic carboxylic acid?
Answer:

  • When benzene diazonium fluoroborate is heated with acetic acid, benzoic acid is obtained.
  • This reaction is used to convert aliphatic carboxylic acid into aromatic carboxylic acid.

Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 118

Question 18.
Write about the isomerisation of alkylisocyanides.
Answer:
When alkyl isocyanides are heated at 250oC, they change into the more stable isomeric cyanides.
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 119

Question 19.
Write the uses of nitroalkanes.
Answer:

  • They are good solvents for a large number of organic compounds including vinyl polymers, cellulose esters, synthetic rubbers, oils, fats, waxes and dyes.
  • Used in organic synthesis.
    Nitromethane reacts with halogen in presence of alkali to form trihalogen derivative, (e.g.,) with chlorine it forms chloropicrin, CCl3NO2 which is used as soil sterilizing agent.
  • Nitroethane is also used as a fuel additive and precursor to Rocket propellants.

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds

Question 20.
How is chloropicrin prepared ?
Answer:
Nitromethane on treatment with Cl2 in presence of NaOH gives chloropicrin.
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 120
Chloropicrin (Trichloronitro methane)

VII. Three mark questions

Question 1.
How are nitro compounds classified?
Answer:
Classification of nitrocompounds
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 121

Question 2.
Convert (i) acetaldelyde into nitro ethane
(ii) acetone into 2-nitropropane
Answer:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 122

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds
Question 3.
Write about the hydrosysis of nitro alkanes
Answer:

  • Hydrolysis can be effected using conc: HCI or conc H2S04
  • Primary nitro alkanes give carboxylic acids.
  • Secondary nitro alkanes give ketones.
  • Tertiary nitro alkanes have no reaction.

Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 123

Question 4.
Write about the classification of amines
Answer:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 124
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 125

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds
Question 5.
Write notes on structure of amines
Answer:

  • Like ammonia, nitrogen atom of amines is trivalent.
  • It carries a lone pair of electron.
  • Nitrogen atom is sp3 hybridised.
  • Out of four sp3 hybridised orbitals, three sp3 orbitals overlap with hydrogen or carbon of alkyl groups.
  • Fourth sp3 orbital contains a lone pair of electron.
  • Amines posses pyramidal geometry.
  • Due to the presence of lone pair of electron the C-N-H or C-N-C bond angle in less than the normal
    tetra hedral bond angle 109.5O
  • In trimethyl amine the C-N-C bond angle is 108O which is lower than the tetrahedral angle and higher than the H-N-H bond angle of 107O in ammonia.
  • This increase is due to the repulson between the bulky methyl groups.
    Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 126

Question 6.
Prepare aniline from
(i) chloro benzene
(ii) Phenol
(iii) nitro benzene
Answer:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 127

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds
Question 7.
Derive an expression for basic strength of amines.
Answer:

  • In aqueous solutions the following equilibrium exists.
  • It lies far to the left, hence amines are weak bases compared to NaOH.

Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 128

  • Basicity constant K bis a measure of the extent to which the amine accepts the hydrogen – ion H+ from water.
  • Larger the value of Kb,, smaller is the value of pKb and stronger is the base.

Question 8.
An organic compound (A) on reduction gives compound (B). (B) on treatment with CHCl3 and alcoholic KOH gives (C) . (C) on catalytic reduction gives N-methyl aniline. Identify A, B, C and write its equation.
Answer:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 129

Compound Name
A Nitrobenzene
B Aniline
C Phenyl Isocyanide

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds
Question 9.
Convert aniline into
(i) p-bromo aniline
(ii) p-nitro aniline
Answer:
(i) To get mono bromo derivatives, -NH2 is first acylated to reduce its activity
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 130
(ii) To get para product, the -NH2 group is protected by acetylation with acetic anhydride. Then the nitrated product is hydrolysed to form the product
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 131

VIII. Five mark questions

Question 1.
Explain structural isomerism exhibited by nitro alkanes
Answer:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 132

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds
Question 2.
Explain the reduction reactions of nitro benzene in various medium.
Answer:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 133

Question 3.
An Organic compound (A) – C7H7NO on treatment with Br2 and KOH gives an amine (B), which gives carbylamine test. (B) upon diazotization to give (C). (C) on coupling_with p-cresol to give
compound (D). Identify A, B, C and D with necessary reaction.
Hofmann’s degradation reaction
Compound (A is Benzamide
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 134Compound B is Aniline (primary amine)
Diazotization reaction:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 135

 

Compound Name
A Benzamide
B Aniline
C Benzene diazoniurn chloride
D 2- phenylazo- 4- Methyl phenol

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds
Question 4.
Write a short note an Libermann’s nitroso test ?
Answer:
Alkyl and aryl secondary amines react with nitrous acid to give N-nitroso amine
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 136

Question 5.
An Organic compound (A) – CNCl react with methyl magnesium Bromide to give, compound B – (C2H3N). B – upon catalytic reduction to give compound C – (C2H7N). C gives carbylamine test, Identify compound A, B and C and write the reactions.
Answer:
An organic Compound A is cyanogon chloride react with methylmagnesium Bromide to give compound B – ethanenitrite – (C2H3N)
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 137
B – upon catalytic reduction to give compound C – Ethananxuie (C2H7N)
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 138

Compound

Name

A cyanogen chloride
B ethanenitrile
C Ethanamine

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds
Question 6.
Explain the action of nitrous acid on three types of amine.
Answer:
Three classes of amines react differently with nitrous acid which is prepared in situ from a mixture of NaNO2 and Hcl.
(a) Primary amines:
Ethylamine reacts with nitrous acid to form ethyldiazonium chloride which is unstable. It is converted into ethanol by liberating N2.
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 139

  • Aniline reacts with nitrous acid at low temperature (273 – 278K) to give benzene diazonium chloride.
  • Benzene diazonium chloride is stable for short time and slowly decomposes even at low
    temperatures.

Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 140
b) Secondary amines:
Alkyl and aryl secondary amines react with nitrous acid to give N-nitroso amine, which is insoluble in water.
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 141
c) Tertiary amines: :
Aliphatic tertiary amine reacts with nitrous acid to form trialkyl ammonium nitrite salt which is
insoluble in water.
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 142
Aromatic tertiary amine reacts with nitrous acid at 273K to give p-nitroso compound
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 143

Question 7.
Explian:
(i) Sand mayer reaction
(ii) Gaftermann reaction
(iii) Baltz – schiemann reaction
Answer:
(i) Sand mayer reaction:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 144
(ii) Gattermann reaction:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 145
(iii) Baltz – Schiemann Reaction:
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 146

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds
Question 8.
Convert benzene diazonium chloride into:
(i) benzene
(ii) iodo benzene
(iii) phenol
(iv) nitrobenzene
(v) phenyl hydrazine
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 147

Question 9.
Explain coupling reactions of benzene diazonium chlorid
Answer:

  • Benzene diazonium chloride reacts with electron rich aromatic compounds like phenol, aniline to form brightly coloured azo compounds.
  • Coupling generally occurs at the para position.
  • If para position is occupied then coupling occurs at the ortho position.
  • Coupling tendency is enhanced if an electron donating group is present at the para-position to – N2 Cl group.
  • This is an electrophilic substitution.

Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 148

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds
Question 10.
Write notes on
(i) Thrope nitrile condensation
(ii) Levine and Hauser acetylation
Answer:
(i) Thrope nitrile condensation :
Self condensation of two molecules of alkylnitrile containing α-H atom in the presence of sodium to form iminonitrile.
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 149
Nitriles containing α-H atom undergo condensation with esters in the presence of sodamide in ether to form ketonitriles,
This is known as Levine – Hauser acetylation.
This reaction involves the replacement of ethoxy (OC2H5) group by methylnitrile (-CH2 CN) group and is called as cyanomethylation reaction.
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 150

 Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds
Question 11.
An aromatic nitro compound (A) on reduction with Sn/HCl gives compound (B) C6H7N which on treatment with Benzoyl chloride in the presence of pyridine to give compound (C). Compound (B) on treatment with CH3Br to give compound (D) which further reacts with NaNO2 /HCl to give compound (E) with yellow oil liquid. Identify (A) to (E) and write the
reactions.
Compound (A) is nitro benzene on reduction with Sn/HCl gives compound (B) is Aniline
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 151
Compound (B) is Aniline reacts with Benzoyl chloride in the presence of pyridine to give compound
(C) is N – phenyl benzamide
Schotten- Baumann reaction
Samacheer Kalvi 12th Chemistry Guide Chapter 13 Organic Nitrogen Compounds 152

Compound Name
A Nitro benzene
B Aniline
C N-phenyl benzamide
D N-Methylaniline
E N-Nitroso methyl phenylamine

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