It is because when NH₃ coordinates to Cu²⁺ ions and it forms the complex [Cu(NH₃)₄]SO₄ copper ions are present in coordination sphere, therefore. they are non-ionisable whereas SO₄^2- ions are counter ions which are ionisable.

(i) Nitration of aniline is accompanied by oxidation. But a mixture of cone. HNO₃ and cone. H₂SO₄ gives m-nitroaniline also. Nitric acid is a strong acid. It protonates aniline forming anilinium ion C₆H₅NH₃⁺ because of positive charge on nitrogen it is meta directing.

p-nitro aniline is prepared in the following three stages

(ii) Aniline reacts with acetyl chloride and acetic anhydride to form corresponding amides called anilides.
\({ C }_{ 6 }H_{ 5 }{ NH }_{ 2 }+\underset { Acetylchloride }{ ClCO{ CH }_{ 3 } } \rightarrow \underset { Acetanilide }{ { C }_{ 6 }{ H }_{ 5 }NHCO{ CH }_{ 3 } } +HCl\)
\({ C }_{ 6 }H_{ 5 }{ NH }_{ 2 }+\underset { Aceticanhydride }{ { CH }_{ 3 }COOCO{ CH }_{ 3 } } \rightarrow \underset { Acetanilide }{ { C }_{ 6 }{ H }_{ 5 }NHCO{ CH }_{ 3 } } +{ CH }_{ 3 }COOH\)

(i) Primary amine react with nitrous acid to form alcohols and nitrogen gas
\(\underset { primary \ amine }{ { CH }_{ 3 }NH_{ 2 } } \rightarrow \underset { unstable }{ { [{ CH } }_{ 3 }-N=N-OH] } \rightarrow { CH }_{ 3 }OH+{ N }_{ 2 }\)
Aliphatic diazonium compound is unstable because of absence of resonance stabilisation.
(ii) Secondary amines react with nitrous acid to form N-nitroso amines which are water insoluble yellow oils.
\(\underset { Secondary \ amine }{ { { (CH }_{ 3 } })_{ 2 }NH } +HO-N=O\rightarrow \underset { N-nitroso \ dimethy \ amine-yellow \ oil\\ (insolube \ in \ water) }{ { (CH }_{ 3 })_{ 2 }N-N=O } \)
(iii) Tertiary amine react with nitrous acid to form trialkyl ammonium nitrite salts which are soluble in water
\(\underset { Tertiary \ amine }{ { (CH }_{ 3 })_{ 2 }N } +HONO\rightarrow \underset { trimethyl \ ammonium \ nitrite\\ (salt \ soluble \ in \ water) }{ { { (CH }_{ 3 }) }_{ 3 }{ NH }^{ + }{ NO }_{ 2 }^{ - } } \)

i) Nitrobenzene ⇾ Nitrosobenzene
When nitrobenzene is treated with glucose and NaOH (alkaline medium) Nitrosobenzene is formed.
\({ C }_{ 6 }{ H }_{ 5 }N{ O }_{ 2 }\rightarrow \underset { Nitrosobenzene }{ { C }_{ 6 }{ H }_{ 5 }NO+{ H }_{ 2 }O } \)
ii) Nitrobenzene ⇾ Azoxybenzene
When nitrobenzene is subjected to reduction with glucose and NaOH forms the intermediate products nitrosobenzene and phenyl hydroxyl amine. These undergo bimolecular condensation reaction to give azoxy benzene.
\({ C }_{ 6 }{ H }_{ 5 }N{ O }_{ 2 }\underrightarrow { Glucose+NaOH } \underset { Nitrosobenzene }{ { C }_{ 6 }{ H }_{ 5 }NO+{ H }_{ 2 }O } \xrightarrow [ { H }_{ 2 }O ]{ \triangle } \underset { Azoxy\quad benzene }{ { C }_{ 6 }{ H }_{ 5 }-N=N{ C }_{ 6 }{ H }_{ 5 } } \)
iii) Nitrobenzene ⇾ Hydrazobenzene
When nitrobenzene is subjected to alkaline reduction in the presence of Zn+NaOH, hydrozo benzene is formed.
\({ C }_{ 6 }{ H }_{ 5 }N{ O }_{ 2 }\underrightarrow { Zn/NaOH } \underset { Nitrosobenzene }{ { C }_{ 6 }{ H }_{ 5 }NH+{ NHC }_{ 6 }{ H }_{ 5 }} \)

(i) CH₃CN (Methyl cyanide) on reduction gives CH₃CH₂NH₂ (ethylamine) because addition of hydrogen takes place at ≡ CN
\({ CH }_{ 2 }-C\equiv N\xrightarrow [ 4H ]{ { LiAH }_{ 4 } } { \underset { Ethylamine\\ (Primary\quad amine) }{ { CH }_{ 3 }-{ CH }_{ 2 }{ NH }_{ 2 } } }\)
Whereas CH₃NC (Methyl isocyanide) on reduction with LiAlH₄ gives secondary amine
\({ CH }_{ 3 }-\underset { \overset { | }{ H } }{ N } -{ CH }_{ 3 }\)

In methyl cyanide, -CN group is attached to alkyl group and by reduction it gives a primary amine wherease in methyl isocyanide -NC group is attached to alkyl group and by reduction it gives a secondary amine.
(ii) (CH₃)₂ NH (Secondary amine) requires 2 moles of CH₃I to give a quaternary salt (crystalline product) whereas (CH₃)₂N (tertiary amine) require only one mole of CH₃I to give the same quaternary salt. It is due to the number of alkyl groups present in amines.
\(\underset { Secondary \ anmine }{ { ( }{ CH }_{ 3 })_{ 2 }-NH+{ 2CH }_{ 3 }I } \rightarrow { { [(CH }_{ 3 })_{ 4 }N] }^{ + }\underset { Tetramethy\\ ammonium \ iodide }{ { I }^{ - } } \)
(iii) Nitration of aniline with cone. HNO₃ results in the formation of m-nitro aniline because nitric acid is a strong acid. It protonates aniline forming anilinium ion C₆H₅NH3+ because of positive charge on nitrogen, it is meta directive and -NO₂ group is substituted at meta position.

(iv) p-Toluidine contains a methyl group which has +I effect (electron withdrawing group and due to this, p-toluidine is a stronger base than p-nitro aniline in which the nitro group is less reactive and it deactivate the benzene rin make it a less basic

(i) Strongly Acidic Medium: When reduced with tin and hydrochloric acid, aromatic nitro compounds are converted to aryl amines.
\({ C }_{ 6 }{ H }_{ 5 }{ NO }_{ 2 }+6[H]\xrightarrow [ or \ Fe/con.HCl ]{ Sn/con.HCl } \underset { Aniline }{ { C }_{ 6 }{ H }_{ 5 }{ NH }_{ 2 }+2 } { H }_{ 2 }Oor\)
(ii) Neutral Medium: When reduced with a neutral, reducing agents like zinc dust and aqueous ammonium chloride, aromatic nitro compounds form aryl hydroxylamines.
\({ C }_{ 6 }{ H }_{ 5 }{ NO }_{ 2 }+4[H]\xrightarrow [ ]{ Zn/{ NH }_{ 4 }Cl } \underset { Phenyl\quad hydroxylamine }{ { C }_{ 6 }{ H }_{ 5 }{ NH }OH+ } { H }_{ 2 }O\)
(iii) Alkaline Medium: In alkaline medium, Nitro benzene on reduction forms the intermediate products nitro so benzene (C₆H₅NO) and phenyl hydroxylamine (C₆H₅NHOH). These undergo bimolecular condensation reaction. According to the appropriate reducing agent in alkaline medium different products are obtained.

(iv) Catalytic Reduction: Lithium Aluminium hydride is a powerful hydride ion donor. So it reduces nitro benzene to Aniline. This reduction can also be carried out by H/Ni.
\({ C }_{ 6 }{ H }_{ 5 }{ NO }_{ 2 }\underrightarrow { LiAl{ H }_{ 4 } } { C }_{ 6 }{ H }_{ 5 }{ NH }_{ 2 }[Aniline]\)
\({ C }_{ 6 }{ H }_{ 5 }{ NO }_{ 2 }\frac { { N }_{ 2 }/Ni }{ Catalytic \ hydrognation } { C }_{ 6 }{ H }_{ 5 }{ NH }_{ 2 }\)
(v) Electrolytic Reduction: When nitro benzene is reduced electrolytically in presence of concentrated sulphuric acid, phenyl hydroxylamine is first produced which rearranges to give p-amino phenol.

i) In increasing order of solubility in water:
\(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{2},\left(\mathrm{C}_{2} \mathrm{H}_{5}\right)_{2} \mathrm{NH}, \mathrm{C}_{2} \mathrm{H}_{5} \mathrm{NH}_{2}  \)
\(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{NH}_{2}>\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{2}>\left(\mathrm{C}_{2} \mathrm{H}_{5}\right)_{2} \mathrm{NH}\)
ii) In increasing order of basic strength:
a. Aniline, p - toluidine and p - nitro aniline
p - toluidine > aniline >p - nitro aniline

 b.  \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{2}, \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NHCH}_{3}, \mathrm{p}-\mathrm{Cl}-\mathrm{C}_{6} \mathrm{H}_{4}-\mathrm{NH}_{2} \)
\(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NHCH}_{3}>\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{2}>\mathrm{p}-\mathrm{Cl}-\mathrm{C}_{6} \mathrm{H}_{4}-\mathrm{NH}_{2}\\ 2^{o} \text { amine } \quad \quad \quad \quad   e^{\ominus} \text { with drawing (group) }\)
(iii) In decreasing order of basic strength in gas phase:
\(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{NH}_{2},\left(\mathrm{C}_{2} \mathrm{H}_{5}\right) \mathrm{NH},\left(\mathrm{C}_{2} \mathrm{H}_{5}\right)_{3} \mathrm{~N} \text { and } \mathrm{NH}_{3}  \)
\(\mathrm{NH}_{3}<\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{NH}_{2}<\left(\mathrm{C}_{2} \mathrm{H}_{5}\right)_{2} \mathrm{~N}<\left(\mathrm{C}_{2} \mathrm{H}_{5}\right)_{3} \mathrm{NH}\\ \quad \quad \quad 1^{0} \text { amine } \quad 2^{0} \text { amine } \quad \quad \quad 3^{0} \text { amine }\)
(iv) In increasing order of boiling point:
\(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{OH},\left(\mathrm{CH}_{3}\right)_{2} \mathrm{NH}, \mathrm{C}_{2} \mathrm{H}_{5} \mathrm{NH}_{2} \)
\(\left(\mathrm{CH}_{3}\right)_{2} \mathrm{NH}>\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{NH}_{2}>\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{OH} \\ 2^{0} \text { amine } \quad \quad1^{0} \text { amine }\)
Generally amines have lower boiling point than alcohol. Due to comparable molecular mass and weaker H-bonds in Amines.
(v) In decreasing order of the pK_b values:
\( \mathrm{C}_{2} \mathrm{H}_{5} \mathrm{NH}_{2}, \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NHCH}_{3},\left(\mathrm{C}_{2} \mathrm{H}_{5}\right)_{2} \mathrm{NH} \text { and } \mathrm{CH}_{3} \mathrm{NH}_{2} \)
\(\left(\mathrm{C}_{2} \mathrm{H}_{5}\right)_{2} \mathrm{NH}<\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{NH}_{2}<\mathrm{CH}_{3} \mathrm{NH}_{2}<\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NHCH}_{3} \)
\(\quad \quad \quad 2^{0} \text { amine } \quad 1^{0} \text { amine } 1^{0} \text { amine } \quad 2^{0} \text { amine } \)
\(\mathrm{PK}_{b}: \quad 3.00\quad < \quad 3.29 \quad < \quad 3.38 \quad<\quad 9.30\)
pK_b ,Due to + 1 effect of C₂H₅ group. Higher the value of pK_b lower is the basicity
(vi) Increasing Order of basic strength:
\(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{2}, \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{~N}\left(\mathrm{CH}_{3}\right)_{2},\left(\mathrm{C}_{2} \mathrm{H}_{5}\right)_{2} \mathrm{NH} \text { and } \mathrm{CH}_{3} \mathrm{NH}_{2} \)
\(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{2}>\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{~N}\left(\mathrm{CH}_{3}\right)_{2}>\mathrm{CH}_{3} \mathrm{NH}_{2}>\left(\mathrm{C}_{2} \mathrm{H}_{5}\right)_{2} \mathrm{NH} \\ \left(\mathrm{pK}_{6}: 9.38 \quad > \quad \quad 8.92 \quad \quad > \quad 3.38 \quad > \quad \quad 3.00\right)\)
Due to + 1 effect of C₂H₅ group.
In decreasing order of basic strength:

Hoffmann's bromide reaction:
When Amides are treated with bromine in the presence of aqueous or ethanolic solution of KOH, primary amines with one carbon atom less than the parent amides are obtained.
\(\underset { \quad \quad \quad amide\\ R=Alkyl(or)Aryl }{ R-\overset { \underset { || }{ O } }{ C } -{ NH }_{ 2 } } \overset { { Br }_{ 2 }/KOH }{ \longrightarrow } \underset { Primary\quad amine }{ R-{ NH }_{ 2 }+{ K }_{ 2 }{ CO }_{ 3 } } +KBr+{ H }_{ 2 }O\)
(ii) Hoffmann's ammonolysis:
When Alkyl halides (or) benzylhalides are heated with alcoholic ammonia in a sealed tube, mixtures of 1°, 2° and 3° amines and quaternary ammonium salts are obtained.
\( { CH }_{ 3 }-Br\overset { \ddot { N } { H }_{ 3 } }{ \underset { \Delta }{ \longrightarrow } } \underset { { 1 }^{ 0 }-amine }{ { CH }_{ 3 }-\ddot { N } { H }_{ 2 } } \overset { { CH }_{ 3 }-Br }{ \longrightarrow } \underset { { 3 }^{ o }-amine }{ \left( { CH }_{ 3 } \right) _{ 2 }\ddot { N } H } \overset { { CH }_{ 3 }Br }{ \longrightarrow } \underset { 3^{ o }-amine }{ \left( { { CH }_{ 3 } } \right) _{ 3 }\ddot { N } } \overset { CH_{ 3 }Br }{ \longrightarrow } \underset { Quartenary \ ammonium\ bromide }{ \left( { CH }_{ 3 } \right) _{ 4 }\overset { + }{ N } { Br }^{ - } } \) 
This is a nucleophilic substitution, the halide ion of alkyl halide is substituted by the -NH₂ group. The product primary amine so formed can also has a tendency to act as a nucleophile and hence if excess alkyl halide is taken, further nucleophilic substitution takes place leading to the formation of quarternary ammonium salt. However, if the process is carried out with excess ammonia, primary amine is obtained as the major product. The order of reactivity of alkylhalides with amines
RI > RBr > RCl
(iii) Gabriel phthalimide synthesis:
Gabriel synthesis is used for the preparation of Aliphatic primary amines. Phthalimide on treatment with ethanolic KOH forms potassium salt of phthalimide which on heating with alkyl halide followed by alkaline hydrolysis gives primary amine. Aniline cannot be prepared by this method because the arylhalides do not undergo nucleophilic substitution with the anion formed by phthalimide.

(iv) Schotten - Baumann reaction :
Aniline reacts with benzoylchloride (C₆H₅COCI) in the presence of NaOH to give N - phenyl benzamide. This reaction is known as Schotten - Baumann reaction. The acylation and benzoylation are nucleophilic substitutions.
\(\underset { Aniline }{ { C }_{ 6 }{ H }_{ 5 }-{ NH }_{ 2 } } +\underset { Benzoyl\quad chloride }{ { C }_{ 6 }{ H }_{ 5 }-\overset { \underset { || }{ O } }{ C } -Cl } \overset { Pyridine }{ \longrightarrow } \underset { N-phenyl\quad benzamide }{ { C }_{ 6 }{ H }_{ 5 }-NH-\overset { \underset { || }{ O } }{ C } -{ C }_{ 6 }{ H }_{ 5 } } +HCl\)
(v) Carbylamine reaction :
Aliphatic (or) aromatic primary amines react with: chloroform and alcoholic KOH to give isocyanides (carbylamines), which has an unpleasant smell. This reaction is known as carbylamines test. This test used to identify the primary amines.
\(\underset { Ethylamine }{ { C }_{ 2 }{ H }_{ 5 }-{ NH }_{ 2 } } +\underset { Chloroform }{ { CHCl }_{ 3 }+3KOH } \longrightarrow \underset { Ethylisocyanide }{ { C }_{ 2 }{ H }_{ 5 }-NC } +3KCl+3{ H }_{ 2 }O\)
(vi) Mustard oil reaction:
(a) When primary amines are treated with carbon disulphide (CS₂), N - alkyldithio carbonic acid is formed which on subsequent treatment with HgCI₂, gives an alkyl isothiocyanate.


(b) When aniline is treated with carbon disulphide, or heated together, S-diphenylthio urea is formed, which on boiling with strong HCI, phenyl isothiocyanate (phenyl mustard oil), is formed.

These reactions are known as Hofmann - Mustard oil reaction. This test is used to identify the primary amines.
(vii) Coupling reactions (or) p-hydroxyazobenzene, p-aminoazobenzene, 2-phenyl azo-4-methyl phenol:
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 -N₂CI- group. This is an electrophilic substitution.

Aryl fluorides and iodides cannot be prepared by direct halogenation and the cyano group cannot be introduced by nucleophilic substitution of chlorine in chlorobenzene. For introducing such a halide group. cyano group -OH, NO₂, etc.. benzenediazonium chloride is a very good intermediate Diazo compounds obtained from the coupling reactions of diazonium salts are coloured and are used as dyes.
(viii) Diazotisation :
Aniline reacts with nitrous acid at low temperature (273 - 278 K) to give benzene. Diazonium chloride which is stable for a short time and slowly decomposes even at low temperatures.This reaction is known as diazotization

(ix) Gomberg reaction :
Benzene diazonium chloride reacts with benzene in the presence of sodium hydroxide to give biphenyl. This reaction in known as the Gomberg reaction

(i) Nitrobenz-ene is used to produce lubricating oils in motors and machinery.
(ii) It is used in the manufacture of dyes, drugs, pesticides, synthelic rubber, aniline and explosives like TNT, TNB.

Addition reaction: Alkyl isocyanides add on halogen, sulphur, and oxygen to form the corresponding addition compounds.

CH₃NC by reaction with POCl₃ in pyridine

Alkyl and aryl secondary amines react with nitrous acid to give N - nitroso amine as yellow oily liquid which is insoluble in water

This reaction is known as Libermann's nitroso test.

X = C₆H₅NH₂; Y = C₆H₅N₂Cl; Z = C₆H₅NO₂.

In simple amines the lone pair of electrons is on nitrogen and hence available for protonation. In amides, on the other hand, the electron pair on nitrogen is delocalized to the carbonyl oxygen through resonance.

Aniline decolourises bromine water with the formation of white precipitate which is 2,4,6-tribromo aniline

(i) CH₃ - CH_{2 -} CH₂NH₂ 1-amino propane
(ii) \({ CH }_{ 3 }-\underset { \overset { | }{ { NH }_{ 2 } } }{ CH } -{ CH }_{ 3 }\)  2-amino propane
(iii) \({ CH }_{ 3 }-{ CH }_{ 2 }-\underset { \overset { | }{ H } }{ N } -{ CH }_{ 3 }\) N - Methyl amino ethane
(iv) \(\quad { CH }_{ 3 }-\overset { \underset { | }{ { CH }_{ 2 } } }{ N } -{ CH }_{ 3 }\) N,N-Dimethyl methanamine

(i) Amines are compounds derived from ammonia by replacing one or more hydrogen atoms by alkyl or aryl group.
(ii) They are classified as primary, secondary and tertiary amines.
(a) When one of the hydrogen atoms in NH₃ is replaced by alkyl, it is primary amine CH₃NH methyl aminefl
(b) If two hydrogen atoms of amine group are replaced by alkyl groups, it is a secondary amine (CH₃)₂ NH- dimethylamine (2°).
(c) If three hydrogen atoms of amine group are replaced by alkyl groups, it is a tertiary amine. (CH₃)₃ N-trimethylamine (3°). Aromatic amine - C₆H₅NH₂ Aline

(i) A - C₆H₅NO₂ - Nitro benzene
(ii) B - C₆H₅NH₂ - Aniline
(iii) C - C₆H₅NC - Phenyl Carbylamine

(i) Aryl cyanide cannot be prepared in this method because of their less reactivity towards nucleophilic substitution. Aryl cyanides are prepared using Sandmeyers reactions.
\(KCH+\underset { methyl \ bromide }{ { CH }_{ 3 }-Br } \rightarrow \underset { ethanenitrile }{ { CH }_{ 3 }-CN } +KBr\)
(ii) By dehydration' of primary amides a aldoximes with P₂O₅
\(\underset { Acetamide }{ { CH }_{ 3 }-CO{ NH }_{ 2 } } \xrightarrow [ { -H }_{ 2 }O ]{ { P }_{ 2 }{ O }_{ 5 } } \underset { Ethaneitrile }{ { CH }_{ 3 }-{ CN } } \)
(iii) \(\underset { Acetaldoximes }{ { CH }_{ 3 }-CH=NOH } \xrightarrow [ { -H }_{ 2 }O ]{ { P }_{ 2 }{ O }_{ 5 } } \underset { Ethaneitrile }{ { CH }_{ 3 }-{ CN } } \)

To get para product, the - NH₂ group is protected by acetylation with acetic anhydride. Then, the nitrated product is hydrolysed to form the product.

To get mono bromo compounds, -NH₂ is first acylated to reduce its activity.

(i) The nitriles containing a-hydrogen also undergo condensation with esters in the presence of sodamide in ether to form ketonitriles.
(ii) This reaction is known as "Levine and hauser" acetylation.
(iii) This reaction involves replacement of ethoxy (OC₂H₅) group by methylnitrile (-CH₂CN) group and is called as cyanomethylation reaction.

(i) The nitrogen in amines possess an unshared pair of electrons (Lone Pair).
(ii) The lone pair of electrons is available for the formation of a new bond with a proton or lewis acid.
(iii) Thus amines are basic in nature and they react with acids to form salts.
(iv) The greater is the number of electron releasing alkyl. groups, the greater the availability of nitrogen's lone pair and stronger the base.
NH₃ < CH₃ - NH₂ < CH₃ - NH - CH₃

(i) Alkyl bromides (or) iodides on heating with ethanolic solution of potassium nitrite gives nitroethane
\(\underset { Ethyl \ bromide }{ { CH }_{ 3 }{ CH }_{ 2 } } -Br+{ KNO }_{ 2 }\xrightarrow [ { SN }_{ 2 } ]{ ethanol/\triangle } \underset { Nitroethane }{ { CH }_{ 3 }{ CH }_{ 2 }-{ NO }_{ 2 } } +KBr\)
The reaction follows SN₂ mechanism.
(ii) Gaseous mixture of methane and nitric acid passed through a red hot metal tube to give nitromethane.

Except methane, other alkanes (upto n- hexane) give a mixture of nitroalkanes due to C-C cleavage. The individual nitro alkanes can be separated by fractional distillation.