Explain why the following systems are not aromatic?
Solution and Explanation
(i)
For the given compound, the number of π-electrons is 6.
By Huckel’s rule,
4n + 2 = 6
4n = 4
n = 1
For a compound to be aromatic, the value of n must be an integer (n = 0, 1, 2…). Since the value of n is an integer.
Hence, the given compound is aromatic in nature.
(ii)
For the given compound, the number of π-electrons is 4.
By Huckel's rule,
4n + 2 = 4
4n = 2
n = \(\frac 12\)
For a compound to be aromatic, the value of n must be an integer (n = 0, 1, 2…), which is not true for the given compound.
Hence, it is not aromatic in nature.
(iii)
For the given compound, the number of π-electrons is 8.
By Huckel's rule,
4n + 2 = 8
4n = 6
n = \(\frac 32\)
For a compound to be aromatic, the value of n must be an integer (n = 0, 1, 2…). Since the value of n is not an integer.
Hence the given compound is not aromatic in nature.
Top Questions on Aromatic Hydrocarbon
- Among the following :
The set which represents aromatic species is- KCET - 2023
- Chemistry
- Aromatic Hydrocarbon
Match List I with List II
List-I Reaction List-II Reagents (A) Hoffmann Degradation (I) Conc.KOH,\(\triangle\) (B) Clemenson reduction (II) CHCl3, NaOH/H3O+ (C) Cannizaro reaction (III) Br2, NaOH (D) Reimer-Tiemann Reaction (IV) Zn-Hg/HCl Choose the correct answer from the option given below:
- JEE Main - 2023
- Chemistry
- Aromatic Hydrocarbon
Chiral complex from the following is
- JEE Main - 2023
- Chemistry
- Aromatic Hydrocarbon
- Which of the following compound(s) is/are aromatic?
- IIT JAM BT - 2023
- Chemistry
- Aromatic Hydrocarbon
The aromatic compound/species with maximum number of x - electrons is
- TS EAMCET - 2023
- Chemistry
- Aromatic Hydrocarbon
Questions Asked in CBSE Class XI exam
- Justify that the following reactions are redox reactions:
- \(CuO(s) + H_2(g) \rightarrow Cu(s) + H_2O(g) \)
- \(Fe_2O_3(s) + 3CO(g) \rightarrow 2Fe(s) + 3CO_2(g) \)
- \(4BCl_3(g) + 3LiAlH_4(s) \rightarrow 2B_2H_6(g) + 3LiCl(s) + 3 AlCl_3 (s) \)
- \(2K(s) + F_2(g) \rightarrow 2K+F^- (s) \)
- \(4 NH_3(g) + 5 O_2(g) \rightarrow 4NO(g) + 6H_2O(g)\)
- CBSE Class XI
- Classical Idea Of Redox Reactions – Oxidation And Reduction Reactions
- Give a brief description of the principles of the following techniques taking an example in each case.(a) Crystallisation (b) Distillation (c) Chromatography.
- CBSE Class XI
- Organic Chemistry- Some Basic Principles and Techniques
- Mention the three phases of the author’s relationship with his grandmother before he left the country to study abroad.
- CBSE Class XI
- The Portrait of a lady
- Calculate the pH of the following solutions:
a) 2 g of TlOH dissolved in water to give 2 litre of solution.
b) 0.3 g of Ca(OH)2 dissolved in water to give 500 mL of solution.
c) 0.3 g of NaOH dissolved in water to give 200 mL of solution.
d) 1mL of 13.6 M HCl is diluted with water to give 1 litre of solution- CBSE Class XI
- Law Of Chemical Equilibrium And Equilibrium Constant
- How many litres of water will have to be added to 1125 litres of the 45% solution of acid so that the resulting mixture will contain more than 25% but less than 30% acid content?
- CBSE Class XI
- inequalities
Concepts Used:
Aromatic hydrocarbon
Aromatic hydrocarbons, sometimes known as arenes, are aromatic organic molecules made up entirely of carbon and hydrogen. In aromatic compounds a benzene ring which is named after the simple aromatic chemical benzene, or a phenyl group when part of a larger structure, is the configuration of six carbon atoms.
Read More: Aromaticity
Reactions of Aromatic Hydrocarbons:
1. Aromatic Substitution Reactions
This reaction involves the replacement of one substituent on the ring of an aromatic hydrocarbon, commonly a hydrogen atom, by a different substituent group.
The common types of aromatic substitution reactions are:
- Nucleophilic aromatic substitution reactions
- Electrophilic aromatic substitution reactions
- Radical nucleophilic aromatic substitution reactions
2. Coupling Reactions
In these types of reactions, the coupling of two fragments that have a radical nature is achieved with the help of a metal catalyst