Write structural formula of the compounds A to D . C 6 H 5 NO 2 → conc . H 2 SO 4 conc . HNO 3 A → NaSH B → 50 % Ethanol , ∆ Zn + NH 4 Cl C → Tollen ' s reagent D

Nitrobenzene already contains a nitro-group. Nitro group is an electron withdrawing group. Therefore, it is a meta directing group. Hence the attachment of a new nitro group occurs in the meta position. Hence the product will be meta-dinitrobenzene. The reaction is shown in the figure. m-dinitrobenzene reacts with NaSH and forms m-nitroaniline. Zinc dust and ammonium chloride convert nitrobenzene to the corresponding hydroxylamine. C 6 H 4 NH 2 - NHOH reduces Tollens reagent (ammoniacal silver nitrate solution) to silver metal and itself is oxidized to C 6 H 4 NH 2 - N = O . C 6 H 4 NH 2 - NO 2 B → 50 % Ethanol , ∆ Zn + NH 4 Cl C 6 H 4 NH 2 - NHOH C → Tollen ' s reagent C 6 H 4 NH 2 - N = O D

Write structural formula of the compounds A to F . (m) C 6 H 5 CONH 2 → Br 2 / KOH A → Br 2 / H 2 O B (n) C 6 H 5 Cl → dry Ether Mg C → ii ) H 3 O + i ) CO 2 / dry Ether D (o) CH 3 3 C - CHO → ∆ conc . NaOH E + F

(m) Hoffmann developed a method for preparation of primary amines by treating an amide with bromine in an aqueous or ethanolic solution of sodium hydroxide. Aniline reacts with bromine water at room temperature to give a white precipitate of 2 , 4 , 6 -tribromoaniline. C 6 H 5 CONH 2 → Br 2 / KOH C 6 H 5 NH 2 Aniline → Br 2 / H 2 O Br 3 C 6 H 2 NH 2 2 , 4 , 6 - tribromoaniline (n) Grignard reagents are obtained by the reaction of haloarenes with magnesium metal in dry ether. Grignard reagents react with carbon dioxide (dry ice) to form salts of carboxylic acids which in turn give corresponding carboxylic acids after acidification with mineral acid. C 6 H 5 Cl → dry Ether Mg C 6 H 5 MgCl → ii ) H 3 O + i ) CO 2 / dry Ether C 6 H 5 COOH (o) Aldehydes which do not have an α-hydrogen atom, undergo self oxidation and reduction (disproportionation) reaction on heating with concentrated alkali. In this reaction, one molecule of the aldehyde is reduced to alcohol while another is oxidised to carboxylic acid salt. CH 3 3 C - CHO → ∆ conc . NaOH CH 3 3 C - CH 2 OH + CH 3 3 C - COONa Therefore, the compounds A , B , C , D , E and F are as follows. A : C 6 H 5 NH 2 Aniline B : Br 3 C 6 H 2 NH 2 2 , 4 , 6 - tribromoaniline C : C 6 H 5 MgCl D : C 6 H 5 COOH E : CH 3 3 C - CH 2 OH F : CH 3 3 C - COONa

Write structural formula of the compounds A to F . (m) C 6 H 5 CONH 2 → Br 2 / KOH A → Br 2 / H 2 O B (n) C 6 H 5 Cl → dry Ether Mg C → ii ) H 3 O + i ) CO 2 / dry Ether D (o) CH 3 3 C - CHO → ∆ conc . NaOH E + F

(m) Hoffmann developed a method for preparation of primary amines by treating an amide with bromine in an aqueous or ethanolic solution of sodium hydroxide. Aniline reacts with bromine water at room temperature to give a white precipitate of 2 , 4 , 6 -tribromoaniline. C 6 H 5 CONH 2 → Br 2 / KOH C 6 H 5 NH 2 Aniline → Br 2 / H 2 O Br 3 C 6 H 2 NH 2 2 , 4 , 6 - tribromoaniline (n) Grignard reagents are obtained by the reaction of haloarenes with magnesium metal in dry ether. Grignard reagents react with carbon dioxide (dry ice) to form salts of carboxylic acids which in turn give corresponding carboxylic acids after acidification with mineral acid. C 6 H 5 Cl → dry Ether Mg C 6 H 5 MgCl → ii ) H 3 O + i ) CO 2 / dry Ether C 6 H 5 COOH (o) Aldehydes which do not have an α-hydrogen atom, undergo self oxidation and reduction (disproportionation) reaction on heating with concentrated alkali. In this reaction, one molecule of the aldehyde is reduced to alcohol while another is oxidised to carboxylic acid salt. CH 3 3 C - CHO → ∆ conc . NaOH CH 3 3 C - CH 2 OH + CH 3 3 C - COONa Therefore, the compounds A , B , C , D , E and F are as follows. A : C 6 H 5 NH 2 Aniline B : Br 3 C 6 H 2 NH 2 2 , 4 , 6 - tribromoaniline C : C 6 H 5 MgCl D : C 6 H 5 COOH E : CH 3 3 C - CH 2 OH F : CH 3 3 C - COONa

Write structural formula of the compounds A to D . C 6 H 5 NO 2 → conc . H 2 SO 4 conc . HNO 3 A → NaSH B → 50 % Ethanol , ∆ Zn + NH 4 Cl C → Tollen ' s reagent D

Nitrobenzene already contains a nitro-group. Nitro group is an electron withdrawing group. Therefore, it is a meta directing group. Hence the attachment of a new nitro group occurs in the meta position. Hence the product will be meta-dinitrobenzene. The reaction is shown in the figure. m-dinitrobenzene reacts with NaSH and forms m-nitroaniline. Zinc dust and ammonium chloride convert nitrobenzene to the corresponding hydroxylamine. C 6 H 4 NH 2 - NHOH reduces Tollens reagent (ammoniacal silver nitrate solution) to silver metal and itself is oxidized to C 6 H 4 NH 2 - N = O . C 6 H 4 NH 2 - NO 2 B → 50 % Ethanol , ∆ Zn + NH 4 Cl C 6 H 4 NH 2 - NHOH C → Tollen ' s reagent C 6 H 4 NH 2 - N = O D

Distinguish between the following two compounds by a chemical reaction: C 6 H 5 NH 2 and C 6 H 5 NHCH 3 .

The given both compounds distinguished by isocyanide test aniline C 6 H 5 NH 2 gives bad smell of isocyanides while methyl aniline C 6 H 5 NHCH 3 does not give this test. C 6 H 5 NH 2 + CHCl 3 + KOH → C 6 H 5 NC + 3 KCl + 3 H 2 O C 6 H 5 NHCH 3 + CHCl 3 + KOH → No reaction .

Write the reagents for the following conversion: C 6 H 5 NO 2 → C 6 H 5 NH 2 → C 6 H 5 NC C 6 H 5 NH 2 → C 6 H 5 N 2 + Cl - → C 6 H 5 CN

C 6 H 5 NO 2 → Sn - HCl C 6 H 5 NH 2 → NaOH CHCl 3 C 6 H 5 NC C 6 H 5 NH 2 → Conc . HCl NaNO 2 C 6 H 5 N 2 + Cl - → CuCN / KCN C 6 H 5 CN

An organic compound (A) of molecular formula C 7 H 5 N on reaction with alkaline H 2 O 2 furnishes (B). Acid hydrolysis of both (A) and (B) produces the same aromatic acid (C) of molecular formula C 7 H 6 O 2 . Reaction of both (A) and (B) with LiAlH 4 gives a primary amine (D) of molecular formula C 7 H 9 N . Identify (A), (B), (C) and (D). Write arrowhead equations for the formation of (B) from (A) and (D) from (A).

On boiling with alkali (or) a dilute mineral acid, the cyanides are hydrolysed to give carboxylic acids. C 6 H 5 CN Ethanenitrile A → H 2 O 2 alkaline C 6 H 5 CONH 2 Benzamide B C 6 H 5 CN Ethanenitrile A → H + / H 2 O C 6 H 5 COOH Benzoic acid c C 6 H 5 CONH 2 Benzamide B → H + / H 2 O C 6 H 5 COOH Benzoic acid c On reduction with LiAlH 4 , alkyl cyanides yields primary amines. C 6 H 5 CN Ethanenitrile A → LiAlH 4 C 6 H 5 CH 2 NH 2 Benzylamine D The amides on reduction with lithium aluminium hydride yield amines. C 6 H 5 CONH 2 Benzamide B → LiAlH 4 C 6 H 5 CH 2 NH 2 Benzylamine D

E M B I B E

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR CHEMISTRY>Chapter 13 - Organic Compounds Containing Nitrogen>West Bengal Board-2019>Q 4

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12th West Bengal Board

IMPORTANT

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Convert aniline to fluorobenzene.

Important Questions on Organic Compounds Containing Nitrogen

HARD

12th West Bengal Board

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR CHEMISTRY>Chapter 13 - Organic Compounds Containing Nitrogen>West Bengal Board-2019>Q 5

Write structural formula of the compounds $A$ to $D$ .

$C_{6} H_{5} {NO}_{2} \to_{conc . H_{2} {SO}_{4}}^{conc . {HNO}_{3}} A \overset{NaSH}{\to} B \to_{50 % Ethanol, ∆}^{Zn + {NH}_{4} Cl} C \overset{Tollen' s reagent}{\to} D$