Aniline in a set of reactions yielded a product, 5.Intermediates formed during the reaction of RCONH. As shown in the following equation, this coupling to the terminal nitrogen should be relatively fast and reversible. SnCl2; 4. (a) ethylamine and acetamide As is mentioned in the textbook, arenediazonium salts are very useful intermediates from which a wide variety of aromatic compounds can be prepared. (c) I,III and IV Unless these azo products are trapped or stabilized in some manner, reversal to the diazonium ion and slow nucleophilic substitution at carbon (with irreversible nitrogen loss) will be the ultimate course of reaction, as described in the previous section. Nitrous acid decomposes very readily and is always made in situ. Some of the more commonly used substitution reactions are shown in the following diagram. The reaction mixture so obtained contains H3O+, (e) 1. Question 59. (b) Carbylamine (b) sodium azide, NaN3 An “arenediazonium salt” is formed by the reaction of an aromatic amine with nitrous acid at 0–5°C, and has the structure shown below. (b) Assertion is true, Reason is true; Reason is not a correct explanation for Assertion. The products of such reactions are highly colored aromatic azo compounds that find use as synthetic dyestuffs, commonly referred to as azo dyes. The LibreTexts libraries are Powered by MindTouch® and are supported by the Department of Education Open Textbook Pilot Project, the UC Davis Office of the Provost, the UC Davis Library, the California State University Affordable Learning Solutions Program, and Merlot. Which of the following should be most volatile? Which of the following compound will not undergo azo coupling reaction with benzene diazonium chloride? CH3CONH2 identify the product formed from the reaction of a given arenediazonium salt with a given arylamine or phenol. (c) potassium cyanide, KCN An amino group is ideal for this purpose. II. (c) II < V < I < IV < III The end product in the following reaction is Naphthalene normally undergoes electrophilic substitution at an alpha-location more rapidly than at beta-sites; however, ortho-coupling is preferred. give an appropriate example to illustrate the high reactivity of arylamines in electrophilic aromatic substitution reactions. 51.Which of the following reagents will convert nitromethane into methylamine ? (b) CH3OCH3 (d) ArCH2NH2, Question 8. Typical reagents : sodium nitrite and aq. CH3CH2Cl, AlCl3; 2. SnCl2; 4. HNO3, H2SO4; 2. (d) potassium phthalimide, C6H4(CO)2N–K+, Question 10. (a) Reaction with HONO Coupling to an activated benzene ring occurs preferentially para to the activating group if that location is free. (c) Alkyl cyanide (c) toluene (a) NaOH—Br2 An aliphatic amine on treatment with alcoholic carbon disulphide and mercuric chloride forms ethyl isothiocyanate, the reaction is known as What will be the product of the following reaction, 38.Which of the following alkene cannot be prepared by de-amination of. (c) 2 and 4 are correct Question 24. When a secondary amine (one hydrogen bonded to the nitrogen atom) reacts with nitrous acid, what's called a nitrosamine is formed. In the chemical reaction, (c) ArNO2 Aniline react with acetaldehyde to form 2 contains the requisite aryl amine unit to react with the nitrosonium cation. (a) there is retention of configuration X can be: Alkanamide, which on Hofmann's reaction gives 1-phenylethylamine, is: The correct order of increasing reactivity of C-X bond towards nucleophile in the following compound is, Amines - Introduction,preparation and properties. (a) H2 (excess)/Pt The term Y is I. CH3CH2NH2 (d) None of the above, Question 11. The product on nitration followed by alkaline hydrolysis gave: 65. (d) 3, 4, 5-tribromonitrobenzene, Question 27. Some examples of azo coupling reactions are shown below. Some of the properties of the two species, $NO_3^-$ and $\ce{H_3O^+}$ are described below. (d) propyl chloride with KCN, Question 32. Question 43. show how the problems associated with carrying out electrophilic aromatic substitution reactions on arylamines can be circumvented by first converting the amine to an amide, and illustrate this process with an appropriate example. C6H5NH2 HNO3, H2SO4; 2. Phenylamine reacts with nitrous acid differently depending on the temperature. (b) nitrobenzene (c) Imine the final product is. (b) V < II < I < III < IV NaNO2, H2SO4; 5. A nitrogenous substance X is treated with HNO2 and the product so formed is further treated with NaOH solution, which produces blue colouration. Among the following which one has the highest cation to anion size ratio? The usual precursor to an aryl amine is the corresponding nitro compound. If you use hydrochloric acid, the solution will contain benzenediazonium chloride. It is removed in the last step. Amongst the compounds given, the one that would form a brilliant coloured dye on treatment with NaNO2 in dil.HCl followed by addition to an alkaline solution of β-naphthol is, Question 21. The compound formed is generally known as: 62.Aniline was acetylated. (a) Schiff’s base Aromatic iodination can only be accomplished directly on highly activated benzene compounds, such as aniline, or indirectly by way of a diazonium intermediate. The result is that many of the bacteria’s amino acids and nucleotides cannot be made, and the bacteria die. (c) addition HNO3, H2SO4; 3. Identify the product in the following sequence Question 29. Propose a synthesis for each of the following molecules from benzene via the diazonium ion. CuCl, (d) 1. (a) II < V < I < III < IV Reason: A tertiary amine has greater number of N—H bonds for H-bonding. 39-42): Each of these questions contains two statements: Assertion and Reason. 10.What is the end product in the following sequences of operations;Acetamide———(P2O5)——->A———(4H)——-> B ? The number of structural isomers possible from the molecular formula $\ce{C3H9N}$ is : Which one of the following is not a primary amine? Cl2, FeCl3; 3. Cl2, FeCl3; 3. Lowering the pH of this solution regenerates phenyldiazoic acid (pKa ca. (a) C6H5CH2NH2 (a) Only II (a) Only II The thermal decomposition of the salt, called the Schiemann reaction, can be quite hazardous. The structure of dopamine is, Question 57. For more information contact us at info@libretexts.org or check out our status page at https://status.libretexts.org. The compound that will react most readily with NaOH to form methanol, is Zn(Hg), HCl, (d) 1. 23.Alkanamide, which on Hofmann’s reaction gives 1-phenylethylamine, is: 24.Alkyl halide (RX) on treatement with KCN followed by reduction leads to formation of: 26.The nitration of nitrobenzene with fuming HNO. identify the product formed when a given arylamine is reacted with aqueous bromine. (a) Hofmann’s reaction To the menu of other organic compounds . The synthesis of sulfanilamide (a sulfa drug) illustrates how the reactivity of aniline can be modified to make possible an electrophilic aromatic substitution. (c) 1, 2, 4-trinitrobenzene These micro‑organisms cannot distinguish between sulfa drugs and p‑aminobenzoic acid; so, when the drug is administered, the bacteria use it to produce a compound which has a structure similar to that of folic acid, but which is unable to act as a coenzyme in essential biochemical processes. Question 42. (a) N,N-dimethyl cyclopropane carboxamide (c) HN(CH3)2 (d) aniline, Question 53. Question 58. A is (a) xylene The reaction mixture so formed contains. The propyl substituent is best introduced by Friedel-Crafts acylation followed by reduction, and this cannot be carried out in the presence of a nitro substituent. (d) benzene. 76.Which one of the following is an amine hormone ? HNO3/H2SO4 at 80°C-100°C forms, which one of the following products? Nitrous acid is unstable and prepared always in situ and written as HONO to represent its structure. Which one of these would yield methyl amine? IV. We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and 1413739. (d) 1, 2-dinitrobenzene, Question 50. (a) ethyl cyanide To absorb all of it, you should use the three subsections indicated in the reading: electrophilic aromatic substitution and overreaction of aniline (Objectives 1 and 2), the preparation of diazonium salts and the Sandmeyer reaction (Objectives 3 and 4), and diazonium coupling reactions (Objective 5).