(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) \(\underset { Acetaldoximes }{ { CH }_{ 3 }-CH=NOH } \xrightarrow [ { -H }_{ 2 }O ]{ { P }_{ 2 }{ O }_{ 5 } } \underset { Ethaneitrile }{ { CH }_{ 3 }-{ CN } } \)

Structure of amines:
(i) Like, ammonia, nitrogen atom of amines is trivalent and carries a lone pair of electron and sp³ hybridised, out of the four sp³ hybridised orbitals of nitrogen, three sp³ orbitals overlap with orbitals of hydrogen (or) alkyl groups of carbon, the fourth sp³ orbital contains a lone pair of electron.
(ii) Hence, amines possess pyramidal geometry. Due to presence of lone pair of electron C-N-H (or) C-N-C bond angle is less than the normal tetrahedral bond angle 109.5°.
For example, the C-N-C bond angle of trimethylamine is 108° which is lower than tetrahedral angle and higher than the H-N-H bond angle of 107°.
(iii) This increase is due to the repulsion between the bulky methyl groups.

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

(i) Repl cementby-OH: When the aqueous solution is boiled, phenol is obtained

This is an example of SN₁ reaction in which C₆H₅N₂CI initially gives C₆H₅⁺ and water is the nudeophile.
(ii) Replacement of RO- (or) RCOO- groups Similarly -N₂CI can be replaced acyloxy group by boiling with carboxylic acids.

(iii) Diazonlum coupling reaction: Diazonium salt reacts with aromatic amine and phenols to give azo compounds of the general formula.
Ar - N = N - Ar'
This reaction is known as Coupling reaction since all these compounds are intensely coloured and used as dyes, thousands of azodyes have been synthesised by this procedure.

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

(i) 
(ii) 
(iii) 
(iv) 

(i) p-nitroaniline is prepared from aniline in three stages as follows:

(ii) 
 

(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) An organic compound (A) with molecular formula C₆H₇N is identified as Aniline C₆H₅NH₂
(ii) Aniline on treatment with HNO₂ / HCl at 273 K gives a clear solution of Benzene diazonium chloride C₆H₅N₂CI the compound (B).
\({ C }_{ 6 }{ H }_{ 5 }{ NH }_{ 2 }+{ HNO }_{ 2 }\xrightarrow [ 273K ]{ NCl } \underset { Benzene \ diazonium \ chloride }{ { C }_{ 6 }{ H }_{ 5 }{ N }_{ 2 }Cl } \)
(iii) An aqueous solution of benzene diazonium chloride on heating gives phenol C₆H₅OH and it is compound (C).
\({ C }_{ 6 }{ H }_{ 5 }{ N }_{ 2 }Cl+{ HOH }\underrightarrow { \triangle } { C }_{ 6 }{ H }_{ 5 }OH-{ N }_{ 2 }+HCl\)

(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.

Acidic nature of nitro alkanes:
(i) The α -H atom of 1⁰ & 2⁰ nitroalkanes show acidic character because of the eIectron with drawing effect of NO₂ group.
(ii) These are more acidic than aldehydes, ketones, ester and cyanides.
(iii) Nitroalkanes dissolve in NaOH solution to form a salt.
(iv) Aci - nitro derivatives are more acidic than nitro form.
(v) When the number of alkyl group attached to α carbon increases, acidity decreases, due to +1 effect of alkyl groups