Amines Important Questions

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Very Short Answer Questions (1 mark)

Ques. How many types of amines are present? 

Ans. Amines are divided into three categories, namely Primary Amine, Secondary Amine, and Tertiary Amine.

Ques. Name the IUPAC name and structure of allylamine?

Ans. The IUPAC name of the compound allylamine is 3-Amino-1-propene. Its structure is as follows:

Allylamine

Ques. Name the most aromatic basic amine?

Ans. Aniline is the most basic aromatic amine that has the structural formula of 

C₆H₅NH₂. Its IUPAC name is benzenamine, and it is sometimes also known as aminobenzene.

Ques. Name one reaction that is used in the preparation of amines using lower amines?

Ans. The Hofmann bromamide reaction is used in the preparation of amines using lower amine. In this amine is heated at a high temperature with bromine along with a base like NaOH or KOH.

Ques. Name the reaction used in the preparation of amines when using the Schmidt reaction?

Ans. The reaction is as follows:

Schmidt Reaction

Ques. Determine the order of boiling points of different types of isomeric amines?

Ans. The order of boiling points of different types of isomeric amines is as follows:

Primary Amines > Secondary Amines > Tertiary Amines

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Short Answer Question (2 marks)

Ques. Explain the basicity of amines?

Ans. The basicity of amines is defined as the capacity of a nitrogen atom to denote a pair of lone electrons. The donation of electrons will change the nature of amines to basic. The shared electron will create a suitable amount of density around the nitrogen atom.

Ques. Explain the role of pyridine in the preparation of amines using the acylation reaction?

Ans. Pyridine is a form of a strong base that will be used as an acceptor when an acid by-product is formed in the acylation reaction. 

• It will shift the equilibrium to the right-hand side of the reaction and help in the removal of hydrochloric acid, which is, HCl.

Ques. How can secondary amines be prepared?

Ans. Secondary amines can be prepared by isonitriles that are reduced with hydrogen atoms in the pressure of a Pt catalyst. The reaction used in the preparation of secondary amines is as follows:

R – NC₄H → R – NH – CH₃

Ques. Write the reactions for the following compounds:

• nitrobenzene → acetanilide

• acetanilide → p-nitroaniline

Ans. The reactions for the following compounds are as follows:

(A) 

(B) 

Ques. What are the factors that are responsible for affecting the basicity of amines?

Ans. The factors responsible for affecting the basicity of amines are as follows:

• The basicity of amines tends to increase when an electron-donating group is added to the amines.
• The basicity decreases when the electron-withdrawing group is removed from the amines.
• It is affected by hybridization.

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Long Answer Question (3 marks)

Ques. What are the physical properties of amines?

Ans. The physical properties of amines are as follows:

• Amines are soluble compounds whose solubility decreases with an increase in the number of carbon atoms.
• They are colorless compounds that tend to have a terrible odor.
• The compounds can easily be created with the help of hydrogen bonds.
• In the case of aromatic compounds, they will donate a lone pair of electrons to the hydrogen bonds.

Ques. What is the difference between amine and amide?

Ans. The differences between amine and amide are as follows:

Ques. Explain Gabriel Phthalimide Synthesis?

Ans. Gabriel Phthalimide Synthesis is a form of chemical reaction that is used in the creation of primary amines after transforming primary alkyl halides. The name of the reaction is derived from a German scientist named Siegmund Gabriel.

• Gabriel Phthalimide Synthesis is also known as Gabriel Synthesis.
• The acid-base reaction is initiated after the addition of potassium hydroxide.
• It will undergo a nucleophilic reaction that results in the formation of imide ions.
• The reaction that is used in Gabriel Phthalimide Reaction is as follows:

Gabriel Synthesis Example

Ques. Explain different types of amines?

Ans. Amines are divided into three categories, which are as follows:

• Primary Amines: Primary amines are formed when an alkyl or aromatic group replaces one hydrogen atom of an ammonia molecule.
• Secondary Amines: Secondary amines are formed when two hydrogen atoms are replaced by alkyl or aryl groups.
• Tertiary Amines: Tertiary amines are formed when the aryl or alkyl group replaces all three hydrogen atoms of ammonia molecules.

Ques. What is the difference between Aniline and Ethylamine?

Ans. The difference between Aniline and Ethylamine are as follows:

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Very Long Answer Question (5 marks)

Ques. What are the uses of amines?

Ans. Some important uses of amines are as follows:

• Amines are used in the manufacturing of rubber and dyes.
• It is most commonly used in pharmaceutical industries.
• The compound is used in the production of plastics and polymers.
• Amines are used as a catalyst in carbamates and insecticides.
• They are used as corrosion inhibitors and in the production of printing inks.

Ques. Explain the preparation of amines by the use of halogenoalkanes?

Ans. The amines are prepared using halogenoalkanes in a sealed tube. During the process of preparation, halogenoalkanes are first heated with a solution of ammonia.

• The heating of the mixture is carried out in the presence of ethanol.
• The reaction cannot be heated in the form of a reflux reaction.
• If the reaction is heated in the form of a reflux reaction, then the ammonia molecule will get released in the form of gas.

The preparation of amines using halogenoalkanes is carried out in two steps, which are as follows:

• In the first step of preparation, ethyl ammonium bromide salt is created.
• The second step carries out the reverse reaction between ammonia and required salt.
• The reaction carried out in preparation of amines are as follows:

CH₃CH₂Br + NH₃ -----------→ CH₃CH₂NH₃ + Br- 

CH₃CH₂NH₃+ Br- + NH₃ -----------→ CH₃CH₂NH₂ + NH₄+Br- 

Ques. What are amines? 

Ans. Amines are the most abundant nitrogenous organic compounds which act as an indirect source of ammonia. They are formed when hydrogen atoms attached to ammonia molecules are replaced by alkyl or aryl compounds.

• Common names and IUPAC names are two techniques used in the process of naming an amine.
• In the IUPAC name, amines are formed by the replacement of 'e' of alkane.
• In this process, a suitable prefix is attached to the amines.
• Amines tend to exhibit chiral properties where nitrogen atoms will create lone pairs of electrons.
• The atoms of nitrogen attached to amines are trivalent in nature.

Ques. What is the difference between amide and imine?

Ans. The difference between amide and imine are as follows:

Ques. What are the steps that are used in the nomenclature of amines?

Ans. The steps used in the nomenclature of amines are as follows:

• First determine the longest chain of carbon that is found in the required compound.
• The numbering of carbon atoms is first initiated either from the halogen atom or carbon atom having the least number.
• Carbon atoms that are forming double or triple bonds with nitrogen atoms are given the least number.
• The halogen atoms attached to the carbon atoms are written in Greek numerical prefixes such as di, tri or tetra.
• In case more than one halogen atom is attached to a carbon atom then in such case the number will be repeated.
• The atoms are arranged in the ascending order of the series.

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