Tiêu đề DPP - 5 Solutions.pdf ✅

Class : XIIth Subject : CHEMISTRY Date : DPP No. : 5 1 (d) Carbylamine reaction is given by aliphatic and aromatic primary amine. CH3CN does not give carbylamine reaction with chloroform because it is not an amine. CH3CN undergoes acidic hydrolysis to give carboxylic acid. CH3CNH2O/H +CH3CONH2H2O/H +CH3COOH + NH3 acetic acid CH3CN undergoes alkaline hydrolysis to give salt of carboxylic acis. CH3CNNaOH H2O CH3CONH2NaOH H2O CH3COONa + NH3 Sodium acetate CH3CN tautomerises to give methyl isocyanide. 5 (b) Aniline reacts with Br2to give 2, 4, 6-tribromoaniline not bromoaniline as CH3 C N C N CH3 NH2 NH2 + 3Br2 Br Br Br 2,4,6-tribromoaniline + 3HBr Topic :- Amines Solutions
6 (d) CH3 ― (an electron releasing (+I )group) increases electron density at N-atom hence, basic nature is increased. C6H5 decreases electron density at N-atom thus basic nature is decreased. (Lone-pair on N in aniline compounds is delocalised along with π-electrons in benzene). Thus, (d) is the strongest base. 7 (b) Urea gives biuret test. Biuret formed gives violet colour with CuSO4 in alkaline medium. 10 (d) or C6H5SO2CI is called Hinsberg reagent. It is used for the distinction of 1°,2°, 3° amine. 11 (a) R—NH2 + CHCl3 + 3KOH⟶3KCl + 3H2O + RNC Offensive smell 12 (a) Ethyl amine, on acetylation, gives N-ethyl acetamide. C2H5NH2CH3COCI ∆ C2H5NHCOCH3 N-ethyl acetamide 13 (b) Aniline on oxidation with per acetic acid, CH3CO3H gives nitrobenzene NH2 I - NH I - CH3 I+ S O O Cl NH2 I - CH3 CH2 NH2 I+
14 (a) Aniline or any 1° amine reacts with aldehyde to form Schiff’s base or anils. 15 (d) Aniline reacts with bromine and give white ppt. of 2, 4, 6 tribromoaniline. 16 (b) R—O—N=O is alkylnitrite having —O—N=O f. gp. ; f. gps are different. 18 (d) Isocyanide on hydrolysis forms primary amine not ammonia. C6H5NC + H2OH +C6H5NH2 + HCOOH 19 (a) Intermolecular H-bonding is more in primary amines than in secondary amines as there are two H-atom available for H-bonding. Tertiary amines do not have intermolecular H- bonding due to absence of H-atom available for H-bonding. Therefore, the order of boiling points of the given amines is as fallows nC4H9NH2 > (C2H5 )2NH > C2H5N(CH3 )2 b.p. 350.8 K b.p. 329.3 K b.p. 310.5 K NH2 NO2 CH3CO3H aniline + CH3CHO N CHCH3 NH2 -H2O acetadehyde schiff's base or anil NO2 NH2 +3 Br2 Br Br Br + 3HBr white ppt. R N O O is nitroalkane having N O O f. gp.
ANSWER-KEY Q. 1 2 3 4 5 6 7 8 9 10 A. D B C B B D B D C D Q. 11 12 13 14 15 16 17 18 19 20 A. A A B A D B B D A C