NCERT Solutions for Class 12 Chemistry Chapter 11 – Alcohols, Phenols and Ethers
NCERT Solutions for Class 12 Chemistry Chapter 11 – Alcohols, Phenols and Ethers is a set of solutions to the questions asked in chapter alcohols, phenols and ethers. In this chapter, you will learn IUPAC nomenclature of alcohols, phenols and ethers. Further, you will learn the reactions involved in the preparation of alcohols from alkenes, aldehydes, ketones and carboxylic acids and the reactions involved in the preparation of phenols from haloarenes, benzene sulphonic acids, diazonium salts and cumene.
Further, this chapter will help you learn the methods of preparation of ethers starting from alcohols, alkyl halides and sodium alkoxides/aryloxides. Here you will also learn how to correlate the physical properties of alcohols, phenols and ethers with their structures. This chapter also discusses the chemical reactions of these classes of compounds on the basis of their functional groups.
There are 33 questions at the end of the chapter. All of these questions have been answered accurately based on the guidelines given by the CBSE Board. These are prepared to cover all the concepts taught in NCERT Solutions for Class 12 Chemistry Chapter 11. The questions asked in this chapter are about the IUPAC nomenclature of alcohols, phenols and ethers, converting names to structures and vice versa, reaction mechanisms, telling products and reaction conditions, structures and names of isomers.
NCERT Class 12 Chemistry Chapter 11
NCERT Solutions for Class 12 Chemistry Chapter 11 – Alcohols, Phenols and Ethers includes all the concepts covered in this chapter in details. The main points given in this chapter are discussed below.
Here you will learn that alcohols and phenols may be classified on the basis of the number of hydroxyl groups present in the structure, as mono–, di–, tri- or polyhydric compounds. The -OH group can be attached to sp3 hybridised carbon atoms in primary, secondary, tertiary, allylic and benzylic alcohols.
CBSE NCERT Class 12 Chemistry Chapter 11 also helps you learn that vinylic alcohols and phenols are compounds where -OH group can be attached to sp2 hybridised carbon atoms. You will also learn that others are simple (symmetrical) or mixed (asymmetrical) compounds, in which two alkyls, two aryl or alkyl aryl groups are attached to an oxygen atom.
This part of the chapter tells about the IUPAC rules to name alcohols, phenols and ethers.
- Structures of Functional Groups
This part of the NCERT CBSE Class 12 Chemistry Chapter 11 discusses the bond angles and bond length of the C-O bond in these compounds and the factors influencing them.
- Preparation of Alcohols and Phenols
This part of the NCERT Class 12 Chemistry Chapter 11 teaches you various methods of preparing alcohol. Alcohols may be prepared from an alkene by its hydration in the presence of an acid or by the hydroboration-oxidation reaction. It is also prepared from carbonyl compounds by catalytic reduction and the action of Grignard reagents.
In this portion of CBSE NCERT Class 12 Book, you come to know that phenols may be prepared by substitution of a halogen atom, in haloarenes or sulfonic acid group in aryl sulfonic acids, by –OH group. Phenols can also be prepared by hydrolysis of diazonium salts and from cumene (industrial scale).
- Physical Properties
This part of the Class 12 Alcohols, Phenols and Ethers chapter discusses that alcohols show higher boiling and greater solubility in water compared to other classes of compounds having comparable molecular masses. The reason behind the special behaviour is the ability of alcohols, phenols and ethers to form intermolecular hydrogen bonding with self and water molecules.
- Chemical Reactions
This part of the chapter tells you that alcohols are chemically versatile and react as both electrophiles and nucleophiles. Alcohols and phenols show acidic character due to the polar nature of the O-H bond. Alcohols react with metals to give the evolution of H2 and phenols react with reactive metals to give respective phenoxides. Electron withdrawing groups attached to phenyl ring increase, whereas electron releasing groups decrease the acidic strength. Alcohols and phenols react with carboxylic acids, acid chlorides and acid anhydrides to yield esters.
This part of the chapter further tells that alcohols undergo nucleophilic substitution with hydrogen halides to give alkyl halides. Alcohols undergo dehydration to give alkenes. Primary alcohols undergo oxidation with mild oxidising agents to provide aldehydes and with strong oxidising agents to give carboxylic acids. Secondary alcohols yield ketones when oxidised with strong oxidation agents. Tertiary alcohols do not undergo oxidation reactions.
- Reactions of Phenols
This part of the chapter teaches you the reactions of phenol. Hydroxyl group in phenols activates the aromatic ring for electrophilic substitution reactions due to resonance effect and also directs the incoming groups to 1- and 4- positions. Phenols undergo the Reimer-Tiemann reaction to produce salicylaldehyde. Phenol undergoes Kolbe’s reaction in basic medium. Reactivity of phenol increases in the presence of NaOH as phenol is converted to phenoxide ion. Phenol undergoes oxidation to give benzoquinone.
- Preparation of Ethers
This part of the NCERT CBSE Class 12 Chapter 11 tells the methods of preparation of ethers like dehydration of alcohols in the presence of acids and Williamson synthesis. The boiling points of ethers resemble those of alkanes, while their solubility is comparable to those of alcohols having the same molecular mass.
- Physical properties of Ethers
This part of the chapter tells that ethers have a net dipole moment as C-O bonds are polar.
- Chemical Reactions of Ethers
This part of the chapter deals with reactions shown by others. Ethers are the least reactive. The C–O bond in ethers can be cleaved by hydrogen halides. The alkoxy group activates the aromatic ring and directs the incoming group to 1- and 4- positions during the electrophilic substitution of aryl ethers.
CBSE NCERT Class 12 Chemistry Chapter 11 Exercise-Discussion
Our NCERT Solutions for Class 12 Chemistry Chapter 11 – Alcohols, Phenols and Ethers answers all 33 questions of the exercise. They cover all the important topics learnt in this chapter. The constituents of the exercise have been listed below.
- Questions 1, 7 and 23 ask you to provide IUPAC names of the given compounds.
- Question 2 asks you to convert names to the structure.
- Question 3 is a direct question on isomeric alcohols.
- Questions 4, 5, 8, 18, 27 and 29 are explanatory questions.
- Questions 9, 10, 17, 28 and 31 ask you to provide equations for a chemical reaction.
- Questions 11, 19, 22, 30 and 33 ask you to write the mechanism of the reaction.
- Questions 12 and 13 ask you to provide the steps for synthesis of given compounds.
- Questions 14 to 16 are based on properties of phenol.
- Questions 20, 21, 24, 26 and 32 ask you about the reaction conditions to bring about chemical conversions.
- Question 25 asks about limitations of Williamson’s synthesis.
There are 12 intext questions asked in CBSE NCERT Class 12 Chemistry Chapter 11 to which best answers have been provided in our solutions. These questions are in addition to the main questions asked at the end and provide an additional scope of practice to you.
Benefits of NCERT Solutions for Class 12th Chemistry Chapter 11 – Alcohols, Phenols and Ethers
Some of the major benefits of referring NCERT Solutions for Class 12 Chemistry Chapter 11 – Alcohols, Phenols and Ethers are as follows –
- They help you build a strong conceptual foundation of the organic compounds containing -OH groups.
- They are the best study source to understand all the principles covered in this chapter and also to effectively revise during exams.
- Organic chemistry needs a lot of things to be remembered by heart, and our solutions provide suitable tips and tricks to help you improve your retention rate
- Our NCERT Solutions contain all types of questions that can be asked from this chapter in your board exams.
They clear your doubts about the concepts taught in this chapter and help you score well in your class 12th board exams.