The correct set(s) of reactions to synthesize benzoic acid starting from benzene is/are
- (i)Br2/Fe (ii)Mg/dry ether (iii)CO2 (iv)H3O⨁
- (i)Br2/Fe (ii)NH3,25°C (iii)NaNO2,dil. HCl, 0° to 5°C (iv)CuCN/KCN (v)dil.HCl,△
- (i)CH3Cl,Anhydrous AlCl3 (ii)KMnO4|⨁OH,△ (iii)H3O⨁
- (i)CH3COCl,Anhydrous AlCl3 (ii)Br2,NaOH (iii)H3O⨁
The Correct Option is A, C, D
Solution and Explanation
In the process of obtaining benzoic acid from benzene, the Friedel–Crafts reactions emerge as a pivotal set of chemical transformations, introduced by Charles Friedel and James Crafts in 1877, which facilitate the introduction of substituents onto an aromatic ring. These reactions fall into two primary categories: alkylation and acylation reactions, both of which operate through the mechanism of electrophilic aromatic substitution.
The molecular composition of benzene, denoted as C6H6, contrasts with that of benzoic acid, which is represented as C6H5COOH. Employing the Friedel-Crafts reaction, benzoic acid is synthesized through the following sequence:
Benzene reacts with Carbon Dichloride (COCl2) in the presence of anhydrous Aluminum Chloride (AlCl3). This process, referred to as Friedel–Crafts Alkylation, yields Benzoyl Chloride (C6H5COCl).
Subsequently, Benzoyl Chloride interacts with water (derived from the anhydrous aluminum chloride molecule), releasing Hydrochloric acid and undergoing conversion into Benzoic Acid.
Noteworthy chemical properties of Benzoic Acid encompass its conversion into Benzyl Alcohol (C6H5 - CH2 - OH) upon reaction with Lithium Aluminum Hydride (LiAlH4).
Another reaction involves the interaction of Benzoic Acid with thionyl chloride (SOCl2) in the presence of pyridine, resulting in the formation of benzoyl chloride (C6H5 - COCl) along with the release of Sulphur dioxide (SO2) and hydrochloric acid (HCl).
It's vital to highlight that in addressing such inquiries, familiarity with the anticipated outcomes of benzene and benzoic acid's reactions with specific substances is crucial.
Benzene, a hexagonal arrangement of six carbon atoms connected by single bonds and bounded to a hydrogen atom on each vertex, belongs to the hydrocarbon class due to its composition of carbon and hydrogen atoms.
On the other hand, benzoic acid is characterized by a benzene ring bearing a carboxyl group, signifying it as an aromatic carboxylic acid. This compound exists as a colorless crystalline solid under normal conditions.
The correct answer is/are option(s):
(A): (i)Br2/Fe (ii)Mg/dry ether (iii)CO2 (iv)H3O⨁
(C): (i)CH3Cl,Anhydrous AlCl3 (ii)KMnO4|⨁OH,△ (iii)H3O⨁
(D): (i)CH3COCl,Anhydrous AlCl3 (ii)Br2,NaOH (iii)H3O⨁
Top Questions on Aldehydes, Ketones and Carboxylic Acids
Ethanal to But-2-enal
- CBSE CLASS XII - 2025
- Chemistry
- Aldehydes, Ketones and Carboxylic Acids
- Give IUPAC name of \( CH_3 = CH - CH = CH - CHO \).
- CBSE CLASS XII - 2025
- Chemistry
- Aldehydes, Ketones and Carboxylic Acids
- Explain the following reactions and write chemical equations involved:
(a) Wolff-Kishner reduction
(b) Etard reaction
(c) Cannizzaro reaction- CBSE CLASS XII - 2025
- Chemistry
- Aldehydes, Ketones and Carboxylic Acids
- Would you expect benzaldehyde to be more reactive or less reactive in nucleophilic addition reactions than propanal? Justify your answer.
- CBSE CLASS XII - 2025
- Chemistry
- Aldehydes, Ketones and Carboxylic Acids
- The acid formed when propyl magnesium bromide is treated with CO$_2$ followed by acid hydrolysis is:
- CBSE CLASS XII - 2025
- Chemistry
- Aldehydes, Ketones and Carboxylic Acids
Questions Asked in WBJEE exam
- Two straight conducting plates form an angle θ where their ends are joined. A conducting bar in contact with the plates and forming an isosceles triangle with them, starts at the vertex at time t = 0 and moves with constant velocity v to the right as shown in the figure. A magnetic field B points out of the page. The magnitude of emf induced at t = 1 second will be:
- WBJEE - 2024
- Electromagnetic induction
- A 2V cell is connected across the points A and B as shown in the figure. Assume that the resistance of each diode is zero in forward bias and infinity in reverse bias. The current supplied by the cell is:
- WBJEE - 2024
- Current electricity
- Consider a circuit where a cell of emf \( E_0 \) and internal resistance \( r \) is connected across the terminal A and B as shown in the figure. The value of \( R \) for which the power generated in the circuit is maximum, is given by:
- WBJEE - 2024
- Current electricity
- In a series LCR circuit, the rms voltage across the resistor and the capacitor are \(30 \, \text{V}\) and \(90 \, \text{V}\) respectively. If the applied voltage is \(50\sqrt{2}\sin\omega t\), then the peak voltage across the inductor is:
- WBJEE - 2024
- Alternating current
- Which of the following statement(s) is/are true in respect of nuclear binding energy?
(i) The mass energy of a nucleus is larger than the total mass energy of its individual protons and neutrons.
(ii) If a nucleus could be separated into its nucleons, an energy equal to the binding energy would have to be transferred to the particles during the separating process.
(iii) The binding energy is a measure of how well the nucleons in a nucleus are held together.
(iv) The nuclear fission is somehow related to acquiring higher binding energy.- WBJEE - 2024
- Nuclear physics
Concepts Used:
Aldehydes, Ketones, and Carboxylic Acids
Aldehydes, Ketones, and Carboxylic Acids are carbonyl compounds that contain a carbon-oxygen double bond. These organic compounds are very important in the field of organic chemistry and also have many industrial applications.
Aldehydes:
Aldehydes are organic compounds that have the functional group -CHO.
Preparation of Aldehydes
Acid chlorides are reduced to aldehydes with hydrogen in the presence of palladium catalyst spread on barium sulfate.
Ketones:
Ketones are organic compounds that have the functional group C=O and the structure R-(C=O)-R’.
Preparation of Ketones
Acid chlorides on reaction with dialkyl cadmium produce ketones. Dialkyl cadmium themselves are prepared from Grignard reagents.
Carboxylic Acid:
Carboxylic acids are organic compounds that contain a (C=O)OH group attached to an R group (where R refers to the remaining part of the molecule).
Preparation of Carboxylic Acids
Primary alcohols are readily oxidized to carboxylic acids with common oxidizing agents such as potassium permanganate in neutral acidic or alkaline media or by potassium dichromate and chromium trioxide in acidic media.