ROUTERA


Chapter 11 Alcohols, Phenols and Ethers

Class 12th Chemistry Chapter MCQs


1. Which of the following is the strongest acid?

a) Methanol
b) Ethanol
c) Phenol
d) Isopropanol

Answer: c) Phenol
Explanation: Phenol is a stronger acid than alcohols due to the resonance stabilization of the phenoxide ion after losing a proton, which alcohols do not exhibit.


2. Which of the following compounds is used as an antiseptic?

a) Acetone
b) Phenol
c) Ethanol
d) Methanol

Answer: b) Phenol
Explanation: Phenol has antiseptic properties and was historically used in disinfectants and antiseptic solutions.


3. The IUPAC name of CH₃CH₂OH is:

a) Ethanol
b) Ethene
c) Methanol
d) Propanol

Answer: a) Ethanol
Explanation: The IUPAC name for CH₃CH₂OH is ethanol, which is a two-carbon alcohol.


4. Which of the following is an example of a phenol?

a) C₆H₆OH
b) CH₃OH
c) CH₃CH₂OH
d) C₆H₅CH₃

Answer: a) C₆H₆OH
Explanation: C₆H₆OH is phenol, which consists of a hydroxyl group (-OH) attached to a benzene ring.


5. Which of the following alcohols does not react with sodium metal?

a) Methanol
b) Ethanol
c) Glycerol
d) Phenol

Answer: d) Phenol
Explanation: Phenol does not react with sodium metal as easily as alcohols because of the resonance stabilization of the phenoxide ion formed.


6. What is the product of the reaction between an alcohol and a carboxylic acid?

a) Ester
b) Ether
c) Aldehyde
d) Ketone

Answer: a) Ester
Explanation: The reaction between an alcohol and a carboxylic acid results in the formation of an ester, which is known as esterification.


7. Which of the following is a characteristic reaction of alcohols?

a) Nucleophilic substitution
b) Electrophilic addition
c) Dehydration
d) Polymerization

Answer: c) Dehydration
Explanation: Alcohols can undergo dehydration (removal of water) to form alkenes in the presence of a strong acid like concentrated sulfuric acid.


8. Which of the following alcohols will undergo oxidation to give a carboxylic acid?

a) Methanol
b) Ethanol
c) Isopropanol
d) Tert-butanol

Answer: b) Ethanol
Explanation: Ethanol can be oxidized to acetic acid, which is a carboxylic acid, by an oxidizing agent like potassium dichromate.


9. Which of the following reagents is used to distinguish between primary, secondary, and tertiary alcohols?

a) Sodium metal
b) Lucas reagent
c) Bromine water
d) Sodium hydroxide

Answer: b) Lucas reagent
Explanation: Lucas reagent (a mixture of zinc chloride and hydrochloric acid) is used to differentiate alcohols based on their reactivity, where tertiary alcohols react immediately, secondary alcohols react slowly, and primary alcohols do not react.


10. Which of the following alcohols can form an aldehyde upon oxidation?

a) Methanol
b) Ethanol
c) Butanol
d) Glycerol

Answer: b) Ethanol
Explanation: Ethanol can be oxidized to acetaldehyde, a two-carbon aldehyde, under mild oxidation conditions.


11. Which of the following is a phenolic compound?

a) Toluene
b) Hydroquinone
c) Methanol
d) Benzene

Answer: b) Hydroquinone
Explanation: Hydroquinone is a phenolic compound with two hydroxyl groups attached to a benzene ring.


12. Which of the following reactions involves the formation of an ether?

a) Williamson’s synthesis
b) Nucleophilic substitution
c) Dehydration
d) Addition reaction

Answer: a) Williamson’s synthesis
Explanation: Williamson’s synthesis is a method used to prepare ethers by reacting an alkoxide ion with a primary halide in an SN2 mechanism.


13. What is the functional group present in alcohols?

a) -COOH
b) -OH
c) -NH₂
d) -COOCH₃

Answer: b) -OH
Explanation: The functional group in alcohols is the hydroxyl group (-OH).


14. Which of the following alcohols is the least soluble in water?

a) Methanol
b) Ethanol
c) Propanol
d) Butanol

Answer: d) Butanol
Explanation: Butanol has a longer hydrophobic tail compared to methanol, ethanol, and propanol, making it less soluble in water.


15. What type of bonding is present in alcohols that allows them to be soluble in water?

a) Covalent bonding
b) Ionic bonding
c) Hydrogen bonding
d) Metallic bonding

Answer: c) Hydrogen bonding
Explanation: Alcohols can form hydrogen bonds with water molecules due to the presence of the hydroxyl (-OH) group, which makes them soluble in water.


16. What is the product when ethanol undergoes dehydration in the presence of concentrated H₂SO₄?

a) Ethene
b) Ethanol
c) Acetaldehyde
d) Ethyl sulfate

Answer: a) Ethene
Explanation: Ethanol undergoes dehydration to form ethene (C₂H₄) when heated with concentrated sulfuric acid.


17. Which of the following compounds is a product of the reaction between phenol and chloroform in the presence of sodium hydroxide?

a) Benzene
b) Salicylic acid
c) Phenyl isocyanate
d) 2,4,6-Trichlorophenol

Answer: b) Salicylic acid
Explanation: Phenol reacts with chloroform (CHCl₃) in the presence of sodium hydroxide to form salicylic acid.


18. Which of the following alcohols can form a ketone upon oxidation?

a) Methanol
b) Ethanol
c) Propanol
d) 2-Propanol

Answer: d) 2-Propanol
Explanation: 2-Propanol is a secondary alcohol, and upon oxidation, it forms acetone, a ketone.


19. Which of the following ethers is commonly used as a solvent in laboratories?

a) Diethyl ether
b) Methyl ether
c) Phenyl ether
d) Tert-butyl ether

Answer: a) Diethyl ether
Explanation: Diethyl ether is commonly used as a solvent in laboratories due to its low boiling point and ability to dissolve a wide range of compounds.


20. The acidic strength of alcohols increases with the:

a) Increase in the number of alkyl groups
b) Decrease in the size of alkyl groups
c) Presence of electron-withdrawing groups
d) Presence of electron-donating groups

Answer: c) Presence of electron-withdrawing groups
Explanation: Electron-withdrawing groups stabilize the negative charge on the oxygen atom after deprotonation, increasing the acidity of alcohols.


21. Which of the following alcohols is a primary alcohol?

a) Methanol
b) Ethanol
c) Isopropanol
d) Butanol

Answer: b) Ethanol
Explanation: Ethanol is a primary alcohol because the hydroxyl group is attached to a carbon atom that is bonded to only one other carbon.


22. Which of the following is a property of ethers?

a) They are highly polar
b) They are easily oxidized
c) They are highly soluble in water
d) They have a low boiling point

Answer: d) They have a low boiling point
Explanation: Ethers generally have lower boiling points compared to alcohols because they cannot form hydrogen bonds with each other, unlike alcohols.


23. Which of the following is used as a local anesthetic?

a) Diethyl ether
b) Phenol
c) Methanol
d) Acetone

Answer: a) Diethyl ether
Explanation: Diethyl ether was historically used as a general anesthetic due to its ability to induce unconsciousness, though it is less commonly used now.


24. Which of the following is used in the preparation of phenol from benzene?

a) Friedel-Crafts alkylation
b) Friedel-Crafts acylation
c) Dow process
d) Kolbe’s reaction

Answer: c) Dow process
Explanation: The Dow process is used for the industrial preparation of phenol from benzene by reacting it with chlorine and sodium hydroxide.


25. Which of the following alcohols is chiral?

a) 1-Butanol
b) 2-Butanol
c) 3-Methyl-2-butanol
d) 2,3-Dimethyl-2-butanol

Answer: b) 2-Butanol
Explanation: 2-Butanol is chiral because it has a carbon center that is attached to four different groups, making it non-superimposable on its mirror image.


26. Which of the following compounds undergoes nucleophilic substitution to form an ether?

a) Phenol
b) Alcohol
c) Aldehyde
d) Alcohol halide

Answer: d) Alcohol halide
Explanation: Alcohol halides can undergo nucleophilic substitution reactions to form ethers when reacted with an alcohol or phenol.


27. Which of the following alcohols is used as a fuel?

a) Methanol
b) Butanol
c) Ethanol
d) Glycerol

Answer: c) Ethanol
Explanation: Ethanol is commonly used as a biofuel in internal combustion engines, either alone or in a mixture with gasoline.


28. Which of the following is an example of a simple ether?

a) Methyl ethyl ether
b) Diethyl ether
c) Phenyl ether
d) All of the above

Answer: d) All of the above
Explanation: All of the listed compounds (methyl ethyl ether, diethyl ether, and phenyl ether) are examples of simple ethers.


29. What is the result of the reaction of phenol with bromine?

a) A white precipitate
b) A yellow precipitate
c) No reaction
d) Formation of a diazonium salt

Answer: a) A white precipitate
Explanation: The reaction of phenol with bromine results in the formation of 2,4,6-tribromophenol, which is a white precipitate.


30. Which of the following alcohols is used to make a perfume base?

a) Ethanol
b) Propanol
c) Methanol
d) Glycerol

Answer: d) Glycerol
Explanation: Glycerol is used as a base in the manufacture of perfumes due to its ability to dissolve aromatic compounds.


31. Which of the following compounds can be synthesized by the dehydration of ethanol?

a) Acetone
b) Ethene
c) Acetic acid
d) Butane

Answer: b) Ethene
Explanation: Ethanol undergoes dehydration in the presence of a strong acid to form ethene (ethylene).


32. Which of the following compounds does not contain a hydroxyl group?

a) Alcohol
b) Phenol
c) Ether
d) Carboxylic acid

Answer: c) Ether
Explanation: Ethers contain an oxygen atom bonded to two carbon atoms and do not have a hydroxyl group (-OH) like alcohols and phenols.


33. Which of the following alcohols does not form an alkene when dehydrated?

a) Tert-butyl alcohol
b) Ethanol
c) Propanol
d) 2-Butanol

Answer: a) Tert-butyl alcohol
Explanation: Tert-butyl alcohol is a tertiary alcohol, and when dehydrated, it undergoes rearrangement to form a more stable carbocation and does not lead to alkene formation in the usual manner.


34. Which of the following compounds is used in the preparation of antioxidants?

a) Hydroquinone
b) Butanol
c) Methanol
d) Toluene

Answer: a) Hydroquinone
Explanation: Hydroquinone is used as an antioxidant in cosmetics and as a stabilizer in polymerization reactions.


35. Which of the following is used to prepare ethers by nucleophilic substitution?

a) Alcohols
b) Carboxylic acids
c) Halides
d) Phenols

Answer: a) Alcohols
Explanation: Alcohols can react with alkyl halides in a Williamson synthesis reaction to form ethers.


36. Which of the following is a property of phenols?

a) They are weak acids
b) They are highly basic
c) They are neutral compounds
d) They form salts with acids

Answer: d) They form salts with acids
Explanation: Phenols are weak acids, and they can form salts with bases like sodium hydroxide.


37. Which of the following alcohols will not undergo oxidation?

a) Methanol
b) Ethanol
c) Butanol
d) Tert-butyl alcohol

Answer: d) Tert-butyl alcohol
Explanation: Tert-butyl alcohol is a tertiary alcohol and is resistant to oxidation due to the absence of a hydrogen atom attached to the carbon bonded to the hydroxyl group.


38. Which of the following alcohols is most likely to undergo nucleophilic substitution?

a) Methanol
b) Ethanol
c) Tert-butyl alcohol
d) Isopropyl alcohol

Answer: a) Methanol
Explanation: Methanol is a primary alcohol and is more reactive in nucleophilic substitution due to the smaller size of the methyl group.


39. Which of the following is used to prepare phenol from cumene?

a) Steam distillation
b) Friedel-Crafts acylation
c) Hock's process
d) Kolbe's reaction

Answer: c) Hock's process
Explanation: Hock’s process is used for the industrial preparation of phenol from cumene by oxidation.


40. Which of the following alcohols can undergo oxidation to form a carboxylic acid?

a) Ethanol
b) Methanol
c) Butanol
d) Tert-butyl alcohol

Answer: a) Ethanol
Explanation: Ethanol can be oxidized to acetic acid, a carboxylic acid.


41. Which of the following is the correct IUPAC name for the compound CH₃-CH₂-O-CH₂-CH₃?

a) Dimethyl ether
b) Ethyl methyl ether
c) Ethoxyethane
d) Butyl ether

Answer: c) Ethoxyethane
Explanation: The IUPAC name for the compound CH₃-CH₂-O-CH₂-CH₃ is ethoxyethane, where the ethoxy group is attached to an ethane backbone.


42. Which of the following compounds is used as an industrial solvent?

a) Diethyl ether
b) Ethanol
c) Phenol
d) Acetone

Answer: a) Diethyl ether
Explanation: Diethyl ether is widely used as an industrial solvent due to its ability to dissolve many organic compounds.


43. What is the product when alcohol reacts with carboxylic acid in the presence of an acid catalyst?

a) Ether
b) Ester
c) Alcohol
d) Aldehyde

Answer: b) Ester
Explanation: When an alcohol reacts with a carboxylic acid in the presence of an acid catalyst, an ester is formed in a process known as esterification.


44. Which of the following alcohols is a secondary alcohol?

a) Methanol
b) Ethanol
c) 2-Propanol
d) 1-Butanol

Answer: c) 2-Propanol
Explanation: 2-Propanol is a secondary alcohol because the hydroxyl group is attached to a carbon atom that is bonded to two other carbon atoms.


45. Which of the following alcohols is most soluble in water?

a) Methanol
b) Ethanol
c) Propanol
d) Butanol

Answer: a) Methanol
Explanation: Methanol is the most soluble in water because it has the smallest size and can form hydrogen bonds with water molecules.


46. Which of the following alcohols is most reactive in electrophilic substitution reactions?

a) Methanol
b) Ethanol
c) Phenol
d) Glycerol

Answer: c) Phenol
Explanation: Phenol is highly reactive in electrophilic substitution reactions due to the electron-donating nature of the hydroxyl group attached to the benzene ring.


47. Which of the following is the correct IUPAC name for CH₃-CH₂-CH₂-OH?

a) Propanol
b) Butanol
c) Methanol
d) Isopropanol

Answer: a) Propanol
Explanation: CH₃-CH₂-CH₂-OH is propanol, a primary alcohol with three carbon atoms.


48. Which of the following ethers is used in anesthesiology?

a) Diethyl ether
b) Methoxyethane
c) Phenyl ether
d) Dimethyl ether

Answer: a) Diethyl ether
Explanation: Diethyl ether was historically used as an anesthetic due to its volatile nature.


49. Which of the following compounds can be formed from the reaction of an alcohol with a strong acid?

a) Aldehyde
b) Alkene
c) Carboxylic acid
d) Ether

Answer: b) Alkene
Explanation: Alcohols can undergo dehydration in the presence of a strong acid to form alkenes.


50. Which of the following statements is true for phenols?

a) Phenols are less acidic than alcohols.
b) Phenols are more acidic than alcohols.
c) Phenols are neutral compounds.
d) Phenols cannot undergo electrophilic substitution.

Answer: b) Phenols are more acidic than alcohols.
Explanation: Phenols are more acidic than alcohols because the negative charge on the oxygen atom after deprotonation can be stabilized by resonance with the aromatic ring.