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Alcohols, Phenols, and Ethers is a crucial chapter in Class 12 Chemistry, assigned a weightage of 6 marks in the annual board examination. This chapter covers the basics of the three organic compounds: Alcohols, Phenols, and Ethers, including their nomenclature, properties, and reactions. The MCQs provided in this article will be very useful for revising key concepts from the chapter. All questions are prepared by subject specialists based on the latest CBSE syllabus for the 2024-25 session. Answers are provided for all questions for the convenience of students. Practice all the MCQs for CBSE Class 12 Chemistry Chapter 7 – Alcohols, Phenols, and Ethers to assess your knowledge and prepare for the CBSE Class 12 Chemistry Board Exam 2024. You can also download all questions and answers in PDF from the link provided in this article.
Scoring higher marks in NEET chemistry is easier if you understand the basic concepts of chemistry chapters. While chemical reactions can be challenging to grasp, understanding the fundamentals of how these reactions occur makes it easier to follow. Preparation and practice are key to scoring the highest marks in NEET Chemistry.
To help you prepare well, here’s an overview of the chapter Alcohols, Phenols, and Ethers, which holds significant weight in the NEET 2024 exams, along with a set of solved MCQs to facilitate learning of the basic concepts.
Overview of Alcohols, Phenols, and Ethers
Alcohols: Alcohols are a homologous series of compounds containing one or more functional hydroxyl (-OH) groups directly attached to an aliphatic carbon atom. An example of a simple alcohol is methyl alcohol (CH3OH). Alcohols are important because they can be converted to and from many other compounds.
Phenols: Phenols contain one or more hydroxyl groups directly attached to an aromatic hydrocarbon group. The simplest phenol is C₆H₅OH. The hydroxyl group is bonded to an sp² hybridized carbon atom of an aromatic ring.
Ethers: Ethers are organic compounds containing an oxygen atom bonded to two alkyl or aryl groups. The general formula for ether is R-O-R’, where R and R’ represent alkyl or aryl groups respectively. Ethers are widely used as solvents because they are relatively unreactive.
Solved MCQs on Alcohols, Phenols, and Ethers
Alcohols, Phenols, and Ethers are widely used in industries and for domestic purposes. Alcohols are formed when a saturated carbon atom is bonded to a hydroxyl (-OH) group. Based on the hydroxyl group, alcohols can be classified into Monohydric, Dihydric, and Trihydric types. Examples include CH3OH, CH3CH2OH, and (CH2OH)2.
Phenols are formed when a hydrogen atom in a benzene molecule is replaced by the -OH group, with the simplest phenol being C6H5OH. Other examples include 2-Methylphenol and Benzene-1,3-diol. Ethers are formed when an oxygen atom is connected to two aryl or alkyl groups. Examples include CH3OCH3 (dimethyl ether) and CH3OCH2CH3 (methoxyethane).
Here are some important MCQs on Alcohols, Phenols, and Ethers for students to test and assess their knowledge on the topic. Practice these to prepare for the CBSE Class 12 Chemistry Board Exam 2024 and the NEET 2024 exams.
MCQ on Class 12 Chemistry Alcohols, Phenols and Ethers
Ques 1. Which of the following processes does not result in the production of alcohol?
a) Acid catalysed hydration of alkenes
b) Free radical halogenation of alkanes
c) Reduction of aldehydes
d) Hydroboration-oxidation of alkenes
Answer: b
Explanation: When alkanes are halogenated by free radicals, they form a mixture of haloalkanes rather than alcohols. Alcohols can be made from alkenes through acid catalysed hydration, and hydroboration-oxidation, and from aldehyde reduction.
Ques 2. Phenol reacts with Bromine in CS₂ at low temperature to give:
a) m-bromophenol
b) o- and p-bromophenol
c) p-bromophenol
d) 2,4,6-tribromophenol
Answer: b
Ques 3. Which of the following is true?
a) Lower alcohols are liquid at room temperature and the higher ones are solid
b) Lower alcohols and higher alcohols, both are liquid at room temperature
c) Higher alcohols are liquid at room temperature and the lower ones are solid
d) Both lower and higher alcohols are solid at room temperature
Answer: a
Ques 4. When phenol reacts with bromine water, what is the result?
a) Brown liquid
b) Colourless gas
c) White precipitate
d) No reaction
Answer: c
Explanation: When phenol is treated with bromine water, a white precipitate is formed, which is 2,4,6-tribromophenol.
Ques 5. An aryl carbon can be found in which of the following compounds?
a) Ethanol
b) Phenol
c) Vinyl alcohol
d) Benzyl alcohol
Answer: b
Explanation: An aryl carbon is the sp² hybridised carbon of an aromatic ring to which the hydroxyl group is connected. The OH group is connected to an aryl carbon in phenol.
Ques 6. Which of the following cannot be made by using Williamson’s synthesis process?
a) Methoxy benzene
b) tert-butyl ethyl ether
c) allyl methyl ether
d) Di-tert-butyl ether
Answer: d
Also Check: Classification of Alcohol, Phenol and Ether and Their Uses with Examples
Ques 7. The Lucas test was carried out on three different compounds: A, B, and C. Compounds A and B were turbid at ambient temperature, while compound C did not become turbid until it was heated. Which one of the compounds is tertiary in structure?
a) A
b) Cannot be determined
c) C
d) A and B
Answer: b
Explanation: It is stated that A and B exhibit turbidity at room temperature, however, it is not stated whether the turbidity appears immediately or over a period of time. So compounds A and B may be tertiary or secondary depending on whether turbidity appears immediately or after 5 minutes respectively. Compound C may be primary.
Ques 8. Heating of phenyl methyl ether with HI produces:
a) Iodobenzene
b) phenol
c) benzene
d) ethyl chloride
Answer: b
Ques 9. Find out the correct order of acidic strength among the following:
a) Ethanol > Water > Phenol
b) Ethanol < Water < Phenol
c) Water < Ethanol < Phenol
d) Phenol > ethanol = Water
Answer: b
Ques 10. The conversion of trialkyl borane to an alcohol does not require which of the following?
a) Sodium hydroxide
b) Water
c) Diborane
d) Hydrogen peroxide
Answer: c
Explanation: In the presence of aqueous NaOH, trialkyl boranes are oxidised by hydrogen peroxide to produce alcohol. This conversion does not require diborane, although it is required for the creation of trialkyl boranes.
Ques 11. The product formed in the following reaction will be:
a) Benzaldehyde
b) Benzene
c) Benzoquinone
d) Benzoic acid
Answer: c
Ques 12. Which of the following alcohols is not polyhydric?
a) Propylene glycol
b) Ethylene glycol
c) Cyclohexanol
d) Benzene-1,2-diol
Answer: c
Explanation: Polyhydric alcohols include two or more hydroxyl groups and are classified as glycols in the common system or diols and triols in the IUPAC system.
Ques 13. Phenol is less acidic than___?
a) Acetic acid
b) p-methoxyphenol
c) p-nitrophenol
d) Ethanol
Answer: a, c
Ques 14. Which of the following will not be soluble in NaHCO₃?
a) 2,4,6-trinitrophenol
b) Benzoic acid
c) o-Nitrophenol
d) Benzene sulphonic acid
Answer: b
Ques 15. Which of the following reagents may be used to distinguish between phenol and benzoic acid?
a) Neutral FeCl₃
b) Aqueous NaOH
c) Tollen’s reagent
d) Molisch reagent
Answer: a
Also Check: NCERT Solutions for Class 12 Chemistry Chapter 11 Alcohols, Phenols and Ethers
Ques 16. Oxygen-containing organic compounds upon oxidation form a carboxylic acid as the only organic product with its molecular mass higher by 14 units. What is the organic compound?
a) A primary alcohol
b) A ketone
c) An aldehyde
d) A secondary alcohol
Answer: a
Ques 17. Which of the following has the lowest boiling point?
a) p-Nitrophenol
b) m-Nitrophenol
c) o-Nitrophenol
d) Phenol
Answer: c
Ques 18. Which of the following compounds is formed when secondary alcohols are oxidised by [O]?
a) Ether
b) Aldehyde
c) Ketone
d) Amine
Answer: c
Explanation: The oxidation of secondary alcohols by a nascent oxygen atom [O] yields the ketone molecule.
Ques 19. Which of the following is formed when glycerol is heated with oxalic acid at 503 K?
a) Glyceric acid
b) Acrolein
c) Allyl alcohol
d) Methanoic acid
Answer: c
Ques 20. Catalytic dehydrogenation of primary alcohol gives a___
a) Ketone
b) Aldehyde
c) Alcohol
d) Esterv
Answer: b
Ques 21. An organic compound with a pleasant odor and 78°C boiling point is boiled with concentrated H₂SO₄. It gives a colorless gas that decolorizes bromine water and alkaline potassium permanganate. What is this organic compound?
a) C₂H₅COOCH₃
b) C₂H₅OH
c) C₂H₅Cl
d) C₂H₆
Answer: b
Ques 22. Dehydration of alcohol is an example of___
a) Addition reaction
b) Elimination reaction
c) Substitution reaction
d) Redox reaction
Answer: b
Also Check: NCERT Exemplar Solutions for Class 12 Chemistry Chapter 11 – Alcohols, Phenols and Ethers
Ques 23. Acid catalysed hydration of alkenes except ethene leads to the formation of___
a) A mixture of secondary and tertiary alcohols
b) A mixture of primary and secondary alcohols
c) Secondary or tertiary alcohols
d) Primary alcohol
Answer: c
Ques 24. Rate of dehydration of alcohols follows the order:
a) 2° > 1° > CH₃OH > 3°
b) 3° > 2° > 1° > CH₃OH
c) 2° > 3° > 1° > CH₃OH
d) CH₃OH > 1° > 2° > 3°
Answer: b
Ques 25. What is the product formed when phenol reacts with bromine water?
a) White precipitate
b) Red precipitate
c) Blue precipitate
d) No precipitate
Answer: a
Ques 26. Which of the following is used for the denaturation of commercial alcohol?
a) Copper sulphate
b) Pyridine
c) Methyl alcohol
d) All of the above
Answer: d
Ques 27. The compound obtained by the reaction of ethene with diborane followed by hydrolysis with alkaline H₂O₂ is___
a) Ethanol
b) Propanol
c) Ethanol
d) Triethyl bromide
Answer: a
Ques 28. The Lucas reagent test is used to distinguish between:
a) Primary, secondary, and tertiary alcohols
b) Aldehydes and ketones
c) Alcohols and phenols
d) Alkenes and alkynes
Answer: a
Ques 29. When salicylic acid is heated with Zn dust, the main product formed will be:
a) Benzene
b) Phenol
c) Toluene
d) Benzoic acid
Answer: d
Ques 30. Which of the following alcohols reacts fastest with conc. HCl and ZnCl₂?
a) Pentan-1-ol
b) 2-methyl butan-1-ol
c) Pentan-2-ol
d) 2-methyl butan-2-ol
Answer: d
