Question

Class 12 Chemistry  MCQ Questions of Alcohols, Phenols and Ethers with Answers?

Answer 1

Class 12 Chemistry MCQ Questions of Alcohols, Phenols and Ethers with Answers make you feel confident in answering the question in the exam & increases your scores to high. You will find the MCQ Questions for class 12 for all Concepts as per the latest syllabus. Practice more on a regular basis with these Chemistry Multiple Choice Questions to improve your subject knowledge & problem-solving skills along with time management.

Given below are MCQ Questions for Class 12 Chemistry Alcohols, Phenols and Ethers which will help you with analyze your knowladge on the topics. The appropriate answers are likewise accommodated your reference.

Practice MCQ Question for Class 12 Chemistry chapter-wise

1. Which of the following reagents can not, be used to oxidise primary alcohols to aldehydes?

(a) CrO₃ in anhydrous medium
(b) KMnO₄ in acidic medium
(c) Pyridinium chlorochromate
(d) Heat in the presence of Cu at 573 K

2. Which of the following alcohols will give the most stable carbocation during dehydration?

(a) 2-methyl-1-propanol
(b) 2-methyl-2-propanol
(c) 1-Butanol
(d) 2-Butanol

3. Which of the following used in manufacture of drugs, plastics, lacquers, polishes, plasticizers

(a) Methanol
(b) Ethanol
(c) Butanol
(d) Aldehyde

4. Monochlorination of toluene in sunlight followed by hydrolysis with aq. NaOH yields.

(a) o-Cresol
(b) m-Cresol
(c) 2, 4-Dihydroxytoluene
(d) Benzyl alcohol

5. IUPAC name of HOCH₂CH₂OH is:

(a) Ethylene glycol
(b) Ethane-1,2-diol
(c) Ethyl-1,2-diol
(d) Ethylene diol

6. Which among the following show tautomerism?

(a) Alcohols
(b) Phenol
(c) Ethers
(d) Anisole

7. Reaction of phenol with chloroform in presence of dilute sodium hydroxide finally introduces which one of the following functional group?

(a) –CHCl₂ 
(b) –CHO
(c) –CH₂Cl 
(d) –COOH

8.  When glycerol is treated with excess of HI, it produces

(a) 2-iodopropane 
(b) Allyl iodide
(c) Propene
(d) Glycerol triiodide

9. Ethylene oxide when treated with Grignard reagent yields

(a) Secondary alcohol
(b) Tertiary alcohol
(c) Cyclopropyl alcohol
(d) Primary alcohol

10. n-propyl alcohol and isopropyl alcohol can be chemically distinguished by which reagent?

(a) PCl5  
(b) Reduction
(c) Oxidation with potassium dichromate
(d) Ozonolysis

11. On heating glycerol with conc. H₂SO₄, a compound is obtained which has bad odour. The compound is

(a) Acrolein
(b) Formic acid
(c) Allyl alcohol
(d) Glycerol sulphate

12. When phenol is treated with CHCl3 and NaOH, the product formed is

(a) Benzaldehyde
(b) Salicylaldehyde
(c) Salicylic acid
(d) Benzoic acid

13. Which of the following will not be soluble in sodium hydrogen carbonate?

(a) 2,4,6-trinitrophenol
(b) Benzoic acid
(c) o-Nitrophenol
(d) Benzenesulphonic acid

14. 1° alcohols preferably undergo dehydration via

(a) E₁
(b) E₂
(c) SN₁ 
(d) SN₂

15. Lucas test is used to distinguish

(a) Phenols
(b) Ethers
(c) Alcohols
(d) Alkyl halides

16. In Lucas test immediate turbidity is caused by

(a) 3° alcohols
(b) 2° alcohols
(c) 1° alcohols 
(d) Phenol

17. Phenols can be distinguished from alcohols by

(a) FeCl₃ (neutral)
(b) Fehling solution
(c) Tollen’s reagent
(d) 2,4-DNP

18. Which of the following will not give positive test with neutral FeCl₃?

(a) Nitrophenol
(b) Phenol
(c) Allyl alcohol
(d) o-cresol

19. Dehydration of tertiary alcohols with Cu at 573 gives

(a) Aldehydes
(b) Ketones
(c) Alkenes
(d) None of these

20. Reaction used for the preparation of ethers is

(a) Reimer-Tiemann reaction
(b) Williamson’s synthesis
(c) Wurtz reaction
(d) Cannizzaro reaction

21. When vapour of a secondary alcohol is passed over heated copper at 573 K, the product formed is -

(a) A carboxylic acid
(b) An aldehyde
(c) A ketone
(d) An alkene

22. The heating of phenylmethyl ethers with HI produces-

(a) Iodobenzene
(b) Phenol
(c) Benzene
(d) Ethyl chloride

23. Reaction of phenol with chloroform in the presence of dilute sodium hydroxide finally introduces, which one of the following functional group?

(a) -CH₂Cl
(b) -COOH
(c) -CHCl₂
(d)  -CHO

24. The process of converting alkyl halides into alcohols involves.............

(a) addition reaction
(b) substitution reaction
(c) dehydrohalogenation reaction
(d) rearrangement reaction

25. IUPAC name of m-cresol is ................

(a) 3-methylphenol
(b) 3-chlorophenol
(c) 3-methoxyphenol
(d) benzene-1,3-diol

Answer 2

1. Answer : (b) KMnO₄ in acidic medium

Explanation: KMnO₄ in acidic medium cannot be used toxidise primary alcohols to aldehydes because convert primary alcohols into carboxylic acid th direct oxidation of primary alcohols to carboxyli acids can be cartied out using KMnO₄.

2. Answer : (b) 2-methyl-2-propanol

Explanation: The tertiary carbocation formed during dehydration of 2-methyl-2-propanol is most stable.

3. Answer : (b) Ethanol

Explanation: Ethanol is used in the manufacture of drugs, plastics, lacquers, polishes, plasticizers, and cosmetics. Ethanol is used in medicine as a topical antiinfective, and as an antidote for ethylene glycol or methanol overdose.

4. Answer : (d) Benzyl alcohol

Explanation:

 

5. Answer : (b) Ethane-1,2-diol

Explanation: IUPAC name of HOCH₂CH₂OH is Ethane-1,2-diol.

6. Answer : (b) Phenol

Explanation: Tautomerism is a type of functional isomerism in which both isomers are in dynamic equilibrium with each other. In phenol, the alpha carbon atom contains hydrogen attached to it. So, it exhibits keto-enol tautomerism as there is a presence of alpha hydrogen atoms.

7. Answer : (b) –CHO

Explanation: Reaction of phenol with chloroform in presence of dilute sodium hydroxide finally introduces aldehyde -CHO functional group and hydroxy group at -ortho position. The reaction is known as Reimer - Tiemann reaction. 

8.  Answer : (a) 2-iodopropane 

Explanation: Glycerol when treated with excess HI produces 2-iodopropane.

9. Answer : (d) Primary alcohol

Explanation:

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10. Answer : (c) Oxidation with potassium dichromate

Explanation:  n− propyl alcohol and isopropyl alcohol gives different product on oxidation with K₂Cr₂O₇.

11. Answer : (a) Acrolein

Explanation:

 

12. Answer : (b) Salicylaldehyde

Explanation: When phenol treated with chloroform in presence of aqueous sodium hydroxide at 340 K to form 2− hydroxybenzaldehyde or salicylaldehyde. This reaction is known as Reimer-Tiemann reaction.

13. Answer : (c) o-Nitrophenol

Explanation: While 2,4,6-trinitrophenol, benzoic acid and benzene sulphonic acid are soluble in NaHCO₃. This reaction is possible in the forward direction if acid is more acidic than H₂CO₃.o-nitrophenol is less acidic than H₂CO₃. Hence, it is not soluble in sodium hydrogen carbonate.

14.  Answer : (b) E₂

Explanation: Primary alcohol dehydrates through the E₂ mechanism. Oxygen donates two electrons to a proton from sulfuric acid H₂SO₄ forming an alkyloxonium ion. Then the nucleophile H₂SO₄ back-side attacks one adjacent hydrogen and the alkyloxonium ion leaves in a concerted process, making a double bond. 

15. Answer : (c) Alcohols

Explanation: The Lucas test in alcohols is a test to differentiate between primary, secondary, and tertiary alcohols. Tertiary alcohols react immediately with Lucas reagent as evidenced by turbidity owing to the low solubility of the organic chloride in the aqueous mixture.

16. Answer : (a) 3° alcohols

Explanation: Tertiary alcohols react immediately with Lucas reagent as evidenced by turbidity owing to the low solubility of the organic chloride in the aqueous mixture.

17.  Answer : (a) FeCl₃ (neutral)

Explanation: Phenol reacts with neutral ferric chloride solution to give violet colouration whereas alcohols do not react.

18. Answer : (c) Allyl alcohol

Explanation: Allyl alcohol does not give positive test with neutral FeCl . Phenol ,nitrophenol and o-cresol gives violet colour with neutral FeCl.

19. Answer : (c) Alkenes

Explanation: Tertiary alcohol when passed over heated Cu at 573 K, dehydration takes place instead of dehydrogenation to gives alkene.

20. Answer : (b) Williamson’s synthesis

Explanation: The Williamson ether synthesis is the most widely used method to produce ethers. It occurs by an SN₂ reaction in which a metal alkoxide displaces a halide ion from an alkyl halide. The alkoxide ion is prepared by the reaction of an alcohol with a strong base such as sodium hydride.

21. Answer : (c) A ketone

Explanation: When the vapours of a primary or a secondary alcohol are passed over heated copper at 573K, dehydrogenation takes place and an aldehyde or a ketone is formed.

22. Answer : (b) Phenol

Explanation:

 

23. Answer : (d)  -CHO

Explanation:

 

24. Answer : (b) substitution reaction

Explanation: In dehydrohalogenation reaction, alkyl halides give alkenes. Rearrangement gives the structural isomers of the reactant while in substitution reaction one of the group or an atom is replaced by other group. Therefore, the process of converting alkyl halides into alcohols involves substitution reaction

25. Answer : (a) 3-methylphenol

Explanation: 

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