Important Questions for CSIR NET Chemical Science 2022 - Aromaticity!

By Renuka Miglani|Updated : May 6th, 2022

Are you preparing for CSIR-NET 2022 and looking for some short and authentic study notes for Chemical Sciences to smoothen your preparation journey? We have got you covered!

Candidates preparing for their upcoming CSIR NET 2022 exam can really make their preparation journey easier with the help of some reliable study notes that cover the topics in the most simple way. We at BYJU'S Exam Prep have come up with the idea of providing Topic Wise Important Questions on Aromaticity of the Chemical Science syllabus. 

The important questions on Organic Chemistry is developed by our experienced subject-matter experts to provide you with the most standard and authentic set of study materials to be focused upon. The students need the best resources for their preparation to clear the CSIR NET 2022 examination, Here are the most reliable important questions to make the topics easier for you and also help you to save your time for the preparations for the upcoming CSIR-NET 2022 exam.

Most Important Questions on Aromaticity - Download PDF

1. The compounds that are aromatic among the following are?

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A. R and S
B. P and Q
C. Q and S
D. P and S

2. Arrange the Benzene, Anthracene and Naphthalene in increasing order of Aromaticity.

A. Benzene > Anthracene > Naphthalene
B. Benzene > Naphthalene > Anthracene
C. Anthracene > Naphthalene > Benzene
D. Naphthalene > Anthracene > Benzene

3. Which one is the aromatic molecule in the following?

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4. The given compound is non-aromatic because -

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A. It does not have delocalization of ∏-electrons.
B. It has maximum angle strain.
C. It does not follow 4n+2 Huckel rule.
D. The molecule is not planar.

5. The correct match for the products of the reactions in Column A with the properties in Column B is -

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A. i–P, ii–S, iii–R, iv–Q
B. i–P, ii–R, iii–Q, iv–S
C. i–Q, ii–R, iii–S, iv–P
D. i–S, ii–Q, iii–R, iv–P

6. From the options given below, aromatic compound is:

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7. Which of the following compound(s) is/are aromatic?

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8. According to simple Huckel theory, select the compound which is not aromatic.

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9. Identify the following as Aromatic, non–Aromatic and Anti aromatic.

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10. The correct statement about the following species is -

A. Both A and B are aromatic
B. A is aromatic and B is antiaromatic
C. A is non-aromatic and B is antiaromatic
D. A is aromatic and B is homoaromatic

 

Solutions

Solution 01:

For a compound to be aromatic, it must follow Huckel Rule, that the compound must have  (4n+2) electrons.

It should be sp2 hybridized, planar, cyclic.

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Compound P, S follow Huckel rule completely. Therefore, they are aromatic in nature.

Correct answer is D.

Solution 02:

Aromaticity order is arranged based on the resonance energy per ring.

On increasing the ring size, electron density per ring decreases Therefore, aromaticity decreases.

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Solution 03:

In compound B,

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There are 16 pi-electrons out of which only 14 pi-electrons are the part of conjugation. Thus, following the Huckel-rule of (4n+2) pi-electrons; the electrons of the pi-bond in the middle of the ring do not participate in the resonance.

Solution 04:

The structure given is of cyclodecapentaene.

It is cyclic.

It is conjugated.

It has 4n+2=10  electrons

But it is not planar and so, non-aromatic. Because the H’s crowd distorts out of plane.

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Solution 05:

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In the first option, we get an aromatic molecule with 10 pi electrons

The second option forms a homoaromatic system.

The third option gives a non -aromatic system as there is no conjugation.

The fourth option is forming an anti-aromatic compound.

Solution 06:

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Both above compounds are aromatic because in pyridine, lone pair of nitrogen is not used in delocalization while in pyrrole lone pair on nitrogen is used in delocalization.

Solution 07:

Molecule given in option C has aromatic sextet and involves a lone pair of S atom in aromaticity.

Solution 08:

 A compound given in option D has eight delocalized -electrons. Hence, it is anti-aromatic in nature.

Solution 09:

(a) It has non-planar structure. All cyclic, completely conjugated but non-planar compounds having (4n+2) electrons and 4n electrons are Non– Aromatic.

(b) It has cyclic planar structure having complete conjugation. Also 6 electrons are participating in conjugation. Hence it shows presence of delocalized (4n + 2) electrons. So, it is Aromatic.

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Solution 10:

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Answer Key:

  1.  D
  2.  B
  3.  B
  4.  D
  5.  A
  6.  D
  7.  C
  8.  B
  9.  C
  10.  B

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