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Chapter Analysis
Advanced30 pages • EnglishQuick Summary
This chapter provides an in-depth exploration of alcohols, phenols, and ethers, detailing their structures, classification, and nomenclature. It discusses the physical properties and various methods of preparation of these compounds from different sources. The chapter also covers chemical reactions, emphasizing electrophilic substitution in phenols and the activation of aromatic rings by hydroxyl groups. Understanding the application of these compounds in daily life and industrial processes is highlighted.
Key Topics
- •Structure of alcohols, phenols, and ethers
- •Classification and nomenclature
- •Preparation methods of alcohols, phenols, and ethers
- •Physical properties and solubility of alcohols and phenols
- •Electrophilic substitution in phenols
- •Chemical reactions of alcohols - oxidation, dehydration
- •Acidity and basicity comparison
- •Industrial applications and importance
Learning Objectives
- ✓Name alcohols, phenols, and ethers according to the IUPAC system.
- ✓Discuss the preparation reactions of alcohols from various chemical sources.
- ✓Compare the reactivity of phenols with alcohols and understand their acidity.
- ✓Explain Williamson ether synthesis and identify its limitations.
- ✓Correlate the physical properties of alcohols, phenols, and ethers with their chemical structures.
- ✓Analyze the chemical behavior of these compounds through their electrophilic and nucleophilic substitution reactions.
Questions in Chapter
Write IUPAC names of the following compounds: (i) (ii) (iii) (iv) (v) (vi) (vii) (viii) (ix) (x) C6H5–O–C2H5 (xi) C6H5–O–C7H15(n–) (xii)
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Write structures of the compounds whose IUPAC names are as follows: (i) 2-Methylbutan-2-ol (ii) 1-Phenylpropan-2-ol (iii) 3,5-Dimethylhexane –1, 3, 5-triol (iv) 2,3 – Diethylphenol (v) 1 – Ethoxypropane (vi) 2-Ethoxy-3-methylpentane (vii) Cyclohexylmethanol (viii) 3-Cyclohexylpentan-3-ol (ix) Cyclopent-3-en-1-ol (x) 4-Chloro-3-ethylbutan-1-ol.
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Draw the structures of all isomeric alcohols of molecular formula C5H12O and give their IUPAC names.
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Explain why propanol has higher boiling point than that of the hydrocarbon, butane?
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Alcohols are comparatively more soluble in water than hydrocarbons of comparable molecular masses. Explain this fact.
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What is meant by hydroboration-oxidation reaction? Illustrate it with an example.
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Additional Practice Questions
What are the primary differences in the reaction mechanisms of alcohols and phenols?
mediumAnswer: The primary difference lies in the acidity; phenols are more acidic due to resonance stabilization of their conjugate bases. This leads to a wider range of electrophilic substitution reactions for phenols compared to alcohols.
Explain the concept of resonance stabilization in phenoxide ions.
hardAnswer: Resonance stabilization in phenoxide involves delocalization of negative charge over the aromatic ring, which enhances the stability compared to isolated phenol ions, increasing the acidity of phenols over alcohols.
How is the solubility of alcohols in water related to their molecular structure?
mediumAnswer: Alcohols are soluble in water primarily due to hydrogen bonding between the hydroxyl group and water molecules. The solubility decreases as the size of the hydrophobic alkyl group increases.
Describe Williamson ether synthesis and its limitations.
mediumAnswer: Williamson ether synthesis involves the formation of ethers from the reaction of an alkyl halide with an alkoxide ion. This reaction best works with primary alkyl halides to avoid elimination reactions that occur with secondary or tertiary halides.
Why do ethers generally have lower boiling points than alcohols?
easyAnswer: Ethers have lower boiling points than alcohols of similar molecular weight due to the lack of hydrogen bonding between ether molecules, which is present in alcohols, resulting in stronger intermolecular forces.