Given below are two statements: Statement I: Aniline reacts with con. H_2SO_4 followed by heating at 453-473 K gives p-aminobenzene sulphonic acid, which gives blood red colour in the 'Lassaigne's test'. Statement II: In Friedel-Crafts alkylation and acylation reactions, aniline forms salt with the AlCl_3 catalyst. Due to this, nitrogen of aniline acquires a positive charge and acts as deactivating group. In the light of the above statements, choose the correct answer from the options given below:

Solution & Explanation

### Core Logic Statement I: Aniline reacting with concentrated H_2SO_4 gives anilinium hydrogensulphate, which on heating at 453-473 K produces sulphanilic acid (p-aminobenzene sulphonic acid). Because sulphanilic acid contains both Nitrogen and Sulphur, it gives a blood-red colouration in Lassaigne's test due to the formation of thiocyanate ion SCN^- which reacts with Fe^3+ to form [Fe(SCN)]^2+. Thus, Statement I is true. Statement II: In Friedel-Crafts reactions, the Lewis acid catalyst AlCl_3 reacts with the lone pair on the nitrogen atom of aniline to form a salt. This generates a positive charge on the nitrogen, transforming the -NH_2 group from a strong activating group into a strong deactivating group, thus preventing the Friedel-Crafts reaction from occurring. Thus, Statement II is true.
Chemical Reactions of Amines diagram for Q70 - JEE Main 2024 Evening
Chemical Reactions of Amines diagram for Q70 - JEE Main 2024 Evening
### Step 1: Final Conclusion Both Statement I and Statement II are true. Option (4) is correct. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 12 Chemistry: Amines Class 11 Chemistry: Organic Chemistry - Some Basic Principles and Techniques

Reference Study Guides

More Amines Previous-Year Questions — Page 2

Q jee_main_2025_07_april_morning Carbylamine Reaction
Which of the following amine(s) show(s) positive carbylamine test? A.
Carbylamine reactant aniline diagram for Q27 - JEE Main 2025
The structures depict Aniline (A) and N-Methylaniline (E) to distinguish primary and secondary aromatic amines.
B. (CH_3)_2NH C. CH_3NH_2 D. (CH_3)_3N E.
Carbylamine reactant aniline diagram for Q27 - JEE Main 2025
The structures depict Aniline (A) and N-Methylaniline (E) to distinguish primary and secondary aromatic amines.
Choose the correct answer from the options given below:
  • A. textA and E Only
  • B. textC Only
  • C. textA and C Only
  • D. textB, C and D Only

Solution

### Related Formula textR-textNH_2 + textCHCl_3 + 3textKOH rightarrow textR-textNC + 3textKCl + 3textH_2textO ### Core Logic Only primary (1^circ) aliphatic and aromatic amines yield a positive carbylamine test (forming foul-smelling alkyl/aryl isocyanides). - **A** is Aniline (primary aromatic amine) rightarrow Positive - **B** is Dimethylamine (secondary aliphatic amine) rightarrow Negative - **C** is Methylamine (primary aliphatic amine) rightarrow Positive - **D** is Trimethylamine (tertiary aliphatic amine) rightarrow Negative - **E** is N-Methylaniline (secondary aromatic amine) rightarrow Negative Thus, only A and C show a positive test. ### Pattern Recognition Shortcut: Look directly for any amine with a plain -textNH_2 functional group. Secondary (-textNH-) and tertiary (-textN-) amines never react. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 12 Chemistry: Amines
Q jee_main_2025_08_april_evening Functional Group Analysis and Identification
An organic compound 'A' undergoes the following sequence of transformations: text'A' xrightarrow[text(ii) H_3O^+]text(i) NaOH text'B' xrightarrow[text(ii) H_2SO_4, Delta]text(i) EtOH text'C' * 'A' shows a positive Lassaigne's test for nitrogen and its molar mass is 121 text g mol^-1. * 'B' gives effervescence with aqueous textNaHCO_3. * 'C' gives a characteristic fruity smell. Identify A, B, and C from the options below:
  • A.
  • B.
  • C.
  • D.

Solution

### Core Logic Let's perform a step-by-step diagnostic analysis: 1. **Molar Mass & Nitrogen Test**: Compound 'A' has a nitrogen atom and a molar mass of 121 text g mol^-1. Let's verify Benzamide (textC_6textH_5textCONH_2): textMass = (7 times 12) + (7 times 1) + 14 + 16 = 84 + 7 + 14 + 16 = 121 text g mol^-1 This matches perfectly. 2. **Alkaline Hydrolysis**: Hydrolysis of benzamide under basic conditions yields benzoic acid upon acidification: textC_6textH_5textCONH_2 xrightarrow[H_3O^+]NaOH textC_6textH_5textCOOH (Compound B) + textNH_3 Benzoic acid reactively gives effervescence with textNaHCO_3 due to the liberation of textCO_2 gas. 3. **Esterification**: Reaction of benzoic acid with ethanol in the presence of acid catalyst results in the creation of ethyl benzoate, an ester with a pleasant fruity smell: textC_6textH_5textCOOH + textEtOH xrightarrowH_2SO_4, Delta textC_6textH_5textCOOEt (Compound C) + textH_2textO
Esterification reaction mechanism diagram for Q28
Esterification reaction mechanism diagram for Q28
### Pattern Recognition "Fruity smell" is an absolute indicator for an ester product. "Effervescence with textNaHCO_3" dictates a carboxylic acid intermediate. Basic hydrolysis converting an organo-nitrogen compound into an acid points directly to an amide or a nitrile—molar mass calculation establishes benzamide over benzonitrile (M = 103). ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 12 Chemistry: Amines Class 12 Chemistry: Aldehydes, Ketones and Carboxylic Acids
Q41 jee_main_2025_29_jan_evening Diazotization and Coupling Reactions
Which one of the following reaction sequences will give an azo dye? (1) Nitrobenzene treated with (i) Sn/HCl, (ii) NaNO_2/HCl, (iii) beta-naphthol, NaOH (2) Benzenesulfonic acid treated with (i) SOCl_2, (ii) NH_3, (iii) Benzyl chloride (3) Benzonitrile treated with (i) 70\% H_2SO_4, (ii) PCl_5, (iii) Aniline (4) Aniline treated with (i) HCl/NaNO_2, (ii) Toluene
  • A. Reaction sequence (1)
  • B. Reaction sequence (2)
  • C. Reaction sequence (3)
  • D. Reaction sequence (4)

Solution

### Core Logic Let's track sequence (1): 1) Nitrobenzene (Ph-NO_2) is reduced using Sn/HCl to form Aniline (Ph-NH_2). 2) Aniline undergoing diazotization with NaNO_2/HCl at cold temperatures (0-5^circC) creates Benzene diazonium chloride (Ph-N_2^+Cl^-). 3) The diazonium salt undergoes a coupling reaction with beta-naphthol in alkaline conditions (NaOH) to synthesize a highly vibrant red-orange azo dye.
Diazotization and Coupling Reactions diagram for Q41 - JEE Main 2025 Evening
Diazotization and Coupling Reactions diagram for Q41 - JEE Main 2025 Evening
### Pattern Recognition The standard sequence for azo dye preparation is: Aromatic Nitro ightarrow Primary Amine ightarrow Diazonium Salt ightarrow Phenol/Naphthol Coupling. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 12 Chemistry: Amines
Q49 jee_main_2025_28_jan_morning Yield and Stoichiometric Calculations
Consider the following sequence of reactions :
Reaction flow pathway for Q49 - JEE Main 2025 Morning
The flowchart tracks a chemical conversion starting from chlorobenzene down to final compound B.
11.25 mg of chlorobenzene will produce mathrmx times 10^-1 mg of product B. (Consider the reactions result in complete conversion.) [Given molar mass of C, H, O, N and Cl as 12, 1, 16, 14 and 35.5mathrmg\,mol^-1 respectively]
Numerical Answer. Answer: 93 to 93

Solution

### Core Logic The reaction sequence details the functional conversion of chlorobenzene down to product B (aniline, with a molar mass of 93\,mathrmg\,mol^-1). Following stoichiometric preservation: textmoles of chlorobenzene = textmoles of Aniline (B) Molar mass of chlorobenzene (mathrmC_6mathrmH_5mathrmCl) = 112.5\,mathrmg\,mol^-1.
Molar stoichiometry relation graph for Q49 - JEE Main 2025 Morning
The flowchart tracks a chemical conversion starting from chlorobenzene down to final compound B.
textmoles = frac11.25 times 10^-3\,mathrmg112.5\,mathrmg\,mol^-1 = 10^-4\,mathrmmol Mass of product B produced: textMass = 10^-4\,mathrmmol times 93\,mathrmg\,mol^-1 = 9.3 times 10^-3\,mathrmg = 9.3\,mathrmmg Expressing in the specified format: 9.3\,mathrmmg = 93 times 10^-1\,mathrmmg Rightarrow x = 93 ### Pattern Recognition Sees: Conversion sequence preserving a 1:1 mole ratio layout. Shortcut: Directly compute target weight via W_B = W_A cdot fracM_BM_A = 11.25 cdot frac93112.5 = 9.3. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 12 Chemistry: Amines
Q37 jee_main_2025_03_april_morning Diazonium Salts and Reactions
Identify [A], [B], and [C], respectively in the following reaction sequence:
Organic aromatic reaction sequence diagram for Q37 - JEE Main 2025 Morning
The reaction shows Aniline reacting with sodium nitrite and hydrochloric acid to produce intermediate A, followed by treatment with potassium iodide to yield B, which then dimerizes via sodium in dry ether to form C.
  • A. Option (1)
  • B. Option (2)
  • C. Option (3)
  • D. Option (4)

Solution

### Core Logic Let us resolve each structural step sequentially: 1. **Step 1:** Aniline undergoes diazotization when treated with textNaNO_2 + textHCl at 273-278text K, forming benzene diazonium chloride [A] (textC_6textH_5textN_2^+textCl^-). 2. **Step 2:** Warming benzene diazonium chloride with potassium iodide (textKI) substitutes the diazonium group with iodine, producing iodobenzene [B] (textC_6textH_5textI). 3. **Step 3:** Treating iodobenzene with sodium metal in dry ether causes a Fittig coupling reaction, dimerizing two phenyl radicals into biphenyl [C] (textC_6textH_5-textC_6textH_5).
Structural reaction verification mechanism for Q37 - JEE Main 2025 Morning
The reaction shows Aniline reacting with sodium nitrite and hydrochloric acid to produce intermediate A, followed by treatment with potassium iodide to yield B, which then dimerizes via sodium in dry ether to form C.
Structural reaction verification mechanism for Q37 - JEE Main 2025 Morning
The reaction shows Aniline reacting with sodium nitrite and hydrochloric acid to produce intermediate A, followed by treatment with potassium iodide to yield B, which then dimerizes via sodium in dry ether to form C.
### Pattern Recognition Shortcut: Aniline ightarrow textNaNO_2/textHCl ightarrow Diazonium salt ightarrow textKI ightarrow Iodobenzene. The final sodium metal treatment triggers a symmetrical radical dimer homocoupling (Fittig reaction) to yield a biphenyl product. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 12 Chemistry: Amines Class 12 Chemistry: Haloalkanes and Haloarenes

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