Q&A - Ask Doubts and Get Answers

Clear All
Aliphatic amines stronger bases than aromatic amines due to resonance in aromatic base the lone pair of electron of N atom delocalised over the benzene ring, which makes it less available for electron donation. On the other hand, in aliphatic amines(), the electron donor group is attached which increase the electron density at N atom. Thus the aliphatic amines are more basic than aromatic amines.    
The extent of inter-molecular hydrogen bonding in primary amines is higher than the secondary amines. Secondary amine has only one hydrogen, and tertiary amines have no hydrogen atom for inter-molecular hydrogen bonding whereas primary amine has two hydrogen atom available for inter-molecular hydrogen bonding. And we know that higher the extent of hydrogen bonding, higher is the boiling...
Protonation of amines gives-        (amide ion) protonation of alcohol gives-    (alkoxide ion) the negative charge is easily accommodated by O atom because it is more electronegative than N atom. So, the amide ion is less stable than the alkoxide ion. Hence amines are less acidic than alcohols.
When aliphatic primary amines react with nitrous acid to form unstable diazonium salts which on further produces alcohol and hydrochloric acid     () with the evolution of dinitrogen gas ().
Aromatic primary amines react with nitrous acid() at 273-278 K to form stable diazonium salts. aniline reacts with nitrous acid to form benzene diazonium chloride.  
Gabriel phthalimide synthesis is used for mainly aliphatic primary amine preparation. Phthalimide reacts with ethanolic potassium hydroxide and produces potassium salt of phthalimide which on heating with alkyl halide followed by alkaline hydrolysis gives corresponding primary amine.   Aromatic amines cannot be produced by this method due to the inability of aryl halides to do nucleophilic...
In this reaction, the chloride ion is replaced by  ion. When diazonium fluoroborate is heated with aqueous sodium nitrite in the presence of copper, the diazonium group is replaced by –NO2 group.      
Aniline reacts with acetic anhydride by a nucleophilic substitution reaction. Here the replacement of H atom from  group is by an acyl group. The product formed is N-phenylethanamide.p. The reaction is carried out in the presence of a base stronger than the amine, like pyridine
Aniline on bromination in the presence of water at room temperature gives a white ppt of 2, 4, 6- tribromoaniline    
Ethanol reduces the benzene diazonium chloride to benzene and oxidises into ethanal (), hydrochloric acid produces as a by-product and evolution of nitrogen gas is also occurring.        
Aniline is a base and   is acid. So, basically, it is acid-base reaction aniline accepts  ions from sulphuric acid and forms a product anilinium hydrogen sulphate.
When benzene diazonium chloride reacts with  it reduced into benzene and  oxidised into , HCl produced as a by-product in this reaction.
The given above reaction is carbylamine reaction in which primary aromatic amines react with chloroform and alc. potassium hydroxide to give isocyanide or carbylamine as a product which is foul-smelling substance.
The molecular formula of C =   it is a Hoffmann bromamide degradation reaction so, the product should be  (aniline) So B should be benzamide () and A should be benzoic acid () Therefore the above reaction proceeds as-
Initially, product A is the reduction of nitrobenzene means it is an aniline. when A react with  it gives benzene diazonium chloride(B). And when B reacts with another aromatic ring (phenol) it's a coupling reaction so it gives azodye (p-Hydroxyazobenzene)         A= Aniline                          B = benzene diazonium chloride                         C= p-Hydroxyazobenzene                 ...
A- ethanamide () B- methenamine () C- methanol () Acetic acid reacts with ammonia, gives ethanamide and the second reaction is Hoffmann bromamide degradation reaction so it removes -CO group and form methenamine and after that the last product is methanol.
A-  B-  C-  The First nitrobenzene reduced to aniline and then it reacts with  to form benzene diazonium salt and is hydrolysed to form phenol()
The structure of A, B, C are respectively  and  In the first reaction, the bromine is replaced by cyanide molecule () and after a reduction by   the CN, molecules become .
The first part is the Sandmeyers reaction so CN replaces the  of the reactant and the product (A) is cynobenzene . On acidic hydrolysis of cynobenzene give product (B) benzoic acid  and benzoic acid react with ammonia (heat) it produces product (C)benzamide  The structure of A, C and B are-  
In the first reaction, the iodine is replaced by CN so the structure of (A) is (propionitrile). On partial hydrolysis, the CN converted in to , So the structure of B is  (propanamide) and the third reactant is Hoffmann bromide degradation reaction, So just remove the -CO group and it becomes a primary aliphatic amine. Thus the structure of C is  (ethanamine)