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JEE Main Organic Chemistry: In this article, you will find answers to previous year’s questions in JEE Main organic chemistry. Our subject matter experts prepare appropriate solutions. The fundamental ideas in the large field of organic chemistry are covered in General Organic Chemistry. In the study of somewhat complex topics, a good comprehension of the concepts covered by GOC is essential (such as the mechanisms of named reactions).
The inductive effect, electrophiles and nucleophiles, isomerism, the resonance effect, and other important topics are covered in this chapter. This is one of the most important chapters in the book. This chapter will likely contain two or three questions for students.
What is the definition of organic chemistry?
Organic chemistry is the discipline of chemistry that studies organic substances scientifically (compounds that contain covalently bonded carbon atoms). Organic chemistry is concerned with the structure and chemical composition of organic molecules, their physical and chemical properties, and the chemical reactions that these compounds undergo. Organic chemistry has made countless contributions to human society, including the development of a variety of pharmaceuticals, polymers, and other natural products. General organic chemistry is a branch of organic chemistry concerned with the creation and design of organic molecules for practical applications.
Because the study of organic chemistry was initially limited to substances created by living creatures, the name “organic” was coined. This was attributed to some kind of ‘vital power’ that living substances possessed that inanimate substances lacked. When Urey Miller produced urea from inorganic chemicals, the aforementioned idea was refuted, although the classification is still in use.
Because of one essential feature shown by the atom carbon, called carbon catenation, organic chemistry is a huge subject.
Let us look at some of the important questions from previous year’s question papers of JEE Organic Chemistry .
Previous Year Questions and Solutions for JEE Main Organic Chemistry
1. Among the following, the most basic compound is:
1.Acetanilide is a kind of acetanilide.
2.Benzylamine is a kind of benzylamine.
3.Nitro aniline is a kind of p-nitroaniline.
4. Amino acid
Solution:
The resonance of lone pair electrons is inversely related to basicity. Benzylamine is a more basic substance. In benzylamine, the electron pairs are not involved in resonance. The lone pair of electrons on the N atom on the ring is delocalized in other amines. The neighbouring CO group causes the delocalization of the lone pair of electrons on the N atom in acetanilide.
As a result, option (2) is the correct answer.
2. Which one has the highest basic strength of amines in an aqueous solution?
what is the pKb value with the least value?
(1) (CH3)3N (CH3)3N (CH3)3N (CH3)
(2) C6H5NH2C6H5NH2C6H5NH2C6
(3) (CH3)2NH (CH3)2NH (CH3)2NH (CH3)
(4) CH3NH2CH3NH2CH3NH2CH3NH2CH
Solution:
Aryalamines are less basic than alkyl amines due to resonance. The lone pair of electrons on N in arylamines is partly shared with the ring and is hence less available for sharing with a proton. The electron-releasing alkyl group enhances the electron density on the nitrogen atom in alkylamines. As a result, the ability of amines to protonate is increased. As a result, the bigger the number of alkyl groups, the higher the basicity of the amine. In the case of trimethylamine, there is a minor variation due to the steric effect. As a result, (CH3)2NH has the lowest pKb value.
As a result, option (3) is the correct answer.
3. In sodium bicarbonate, which of the following compounds will not dissolve?
(1) Sulphonic acid of benzene
(2)Benzoic acid (sometimes known as benzoic acid) is a type of
(3)o-Nitrophenol (nitrophenol) (nitrophenol) (nit
(4) Trinitrophenol (2, 4, 6)
Solution:
Stronger acids, such as benzene sulphonic acid and benzoic acid, react with sodium bicarbonate. o-Nitrophenol is a very weak acid that reacts with sodium bicarbonate but not with water. Sodium bicarbonate will not dissolve o-nitrophenol. Trinitrophenol has greater acidity and reacts with sodium bicarbonate. 2, 3, 6 – Trinitrophenol has a higher acidity and reacts with sodium bicarbonate.
As a result, option (3) is the correct answer.
4. In a positive nitrogen test with a Lassaigne solution of an organic molecule, the chemical generated is
(1) Fe4[Fe(CN)6] Fe4[Fe(CN)6] Fe4[Fe(CN)3
(2) [Fe(CN)5NOS] Na4[Fe(CN)5NOS]
(3) Fe(CN)3 Fe(CN)3 Fe(CN)3 Fe(CN)
(4) Na3[Fe(CN)6] Na3[Fe(CN)6] Na3[Fe(CN)6
Solution:
The Prussian blue coloured complex chemical ferric ferrocyanide is generated in the positive test for nitrogen with the Lassaigne solution of an organic molecule.
As a result, option 1 is the correct answer.
5. The formula, in general, It’s possible that CnH2nO2 is for an open chain.
carboxylic acids (first)
a pair of diols
a) dialdehydes b) dialdehydes c)
diketones (4)
Solution:
Open chain carboxylic acid or ester could be represented by the generic formula CnH2n02.
As a result, option 1 is the correct answer.
Also read: JEE Main Exam Mode
6.The right decreasing order of acid strength among the following oxoacids is:
(1) HClO4 > HClO3 > HClO2 > HOCl HClO4 > HClO3 > HClO2 > HOCl
(2) HClO2 > HClO4 > HClO3 > HOCl HClO2 > HClO4 > HClO3 > HOCl
(3) HClO2 > HClO3 > HClO4 HOCl > HClO2 > HClO3 > HClO4
(4) HClO4 > HOCl > HClO2 > HClO3 > HClO2 > HClO3
Solution:
The oxidation number is directly proportional to the acidic strength. The oxidation state of the centre atom increases as the acid intensity increases.
As a result, option 1 is the correct answer.
7. Ortho-Nitrophenol is less water-soluble than p– and m– Nitrophenols for the following reasons:
(1) o–Nitrophenol has a lower melting point than the m– and p– isomers.
(2) In steam, o–Nitrophenol is more volatile than the m– and p– isomers.
(3) Intramolecular H–bonding is observed in o–Nitrophenol.
(4) o–Nitrophenol demonstrates H–bonding between molecules
Solution:
O-nitrophenol contains intramolecular H-bonding. As a result, water solubility is reduced.
As a result, option (3) is the correct answer.
8. Which one of the following confirmations of cyclohexane is chiral?
(1) Twist boat
(2) Rigid
(3) Chair
(4) Boat
Solution:
The twist boat is chiral because it does not have a plane of symmetry.
Hence option (1) is the answer.
9. Increasing order of stability among the three main conformations (i.e. Eclipse, Anti, Gauche) of 2-trifluoroethanol is
(1)Eclipse, Gauche, Anti
(2)Gauche, Eclipse, Anti
(3)Eclipse, Anti, Gauche
(4)Anti, Gauche, Eclipse
Solution:
Eclipse is the least stable and Gauche is the most stable.
Hence option (3) is the answer.
10. Which types of isomerism are shown by 2,3-dichlorobutane?
(1) Diastereo
(2) Optical
(3) Geometric
(4) Structural
Solution:
2,3- dichlorobutane shows optical isomerism.
Hence option (2) is the answer.
11. Due to the presence of an unpaired electron, free radicals are
(1)Chemically reactive
(2) Chemically inactive
(3) Anions
(4) Cations
Solution:
Due to the presence of an unpaired electron, the free radicals are chemically active.
Hence option (1) is the answer.
12. Which one of the following does not have sp2 hybridized carbon?
(1) Acetone
(2) Acetamide
(3) Acetonitrile
(4) Acetic acid
Solution:
Acetonitrile is having only sp3 and sp hybridized carbon atoms.
Hence option (3) is the answer.
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