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Alcohols, Phenols and Ethers: questions with answers

Class 12 Chemistry, Chapter 7 (NCERT). 15 questions by concept. Open “Show answer” for the answer and why.

How to teach this chapter · Common misconceptions & worked visual for this chapter

Classification, nomenclature, and structure

Question 1

Which statement gives the sound Class XII chemistry for ‘Classification, nomenclature, and structure’?

  1. (a)For classification, nomenclature, and structure, the relevant direction, trend, product ordering, or cause-and-effect relation is always the exact reverse of the governing rule.
  2. (b)The same conclusion about classification, nomenclature, and structure remains valid after changing the reagent, molecular structure, medium, or condition that controls the result.
  3. (c)Only the name of the substance is needed for classification, nomenclature, and structure; equations, structures, stoichiometry, evidence, and conditions cannot change the answer.
  4. (d)Alcohols, phenols, and ethers are distinguished by whether oxygen is bonded to saturated carbon, an aromatic ring, or two carbon groups. Hydrogen bonding, bond polarity, and resonance explain nomenclature, boiling points, solubility, acidity, and reaction patterns.
Show answer

(d) Alcohols, phenols, and ethers are distinguished by whether oxygen is bonded to saturated carbon, an aromatic ring, or two carbon groups. Hydrogen bonding, bond polarity, and resonance explain nomenclature, boiling points, solubility, acidity, and reaction patterns.

Alcohols, phenols, and ethers are distinguished by whether oxygen is bonded to saturated carbon, an aromatic ring, or two carbon groups. Hydrogen bonding, bond polarity, and resonance explain nomenclature, boiling points, solubility, acidity, and reaction patterns.

Question 2

Which principle should be retained when checking an inference about ‘Classification, nomenclature, and structure’?

  1. (a)Alcohols, phenols, and ethers are distinguished by whether oxygen is bonded to saturated carbon, an aromatic ring, or two carbon groups. Hydrogen bonding, bond polarity, and resonance explain nomenclature, boiling points, solubility, acidity, and reaction patterns.
  2. (b)Only the name of the substance is needed for classification, nomenclature, and structure; equations, structures, stoichiometry, evidence, and conditions cannot change the answer.
  3. (c)The same conclusion about classification, nomenclature, and structure remains valid after changing the reagent, molecular structure, medium, or condition that controls the result.
  4. (d)For classification, nomenclature, and structure, the relevant direction, trend, product ordering, or cause-and-effect relation is always the exact reverse of the governing rule.
Show answer

(a) Alcohols, phenols, and ethers are distinguished by whether oxygen is bonded to saturated carbon, an aromatic ring, or two carbon groups. Hydrogen bonding, bond polarity, and resonance explain nomenclature, boiling points, solubility, acidity, and reaction patterns.

Alcohols, phenols, and ethers are distinguished by whether oxygen is bonded to saturated carbon, an aromatic ring, or two carbon groups. Hydrogen bonding, bond polarity, and resonance explain nomenclature, boiling points, solubility, acidity, and reaction patterns.

Question 3

Which statement correctly governs a new case involving classification, nomenclature, and structure?

  1. (a)Alcohols, phenols, and ethers are distinguished by whether oxygen is bonded to saturated carbon, an aromatic ring, or two carbon groups. Hydrogen bonding, bond polarity, and resonance explain nomenclature, boiling points, solubility, acidity, and reaction patterns.
  2. (b)Only the name of the substance is needed for classification, nomenclature, and structure; equations, structures, stoichiometry, evidence, and conditions cannot change the answer.
  3. (c)The same conclusion about classification, nomenclature, and structure remains valid after changing the reagent, molecular structure, medium, or condition that controls the result.
  4. (d)For classification, nomenclature, and structure, the relevant direction, trend, product ordering, or cause-and-effect relation is always the exact reverse of the governing rule.
Show answer

(a) Alcohols, phenols, and ethers are distinguished by whether oxygen is bonded to saturated carbon, an aromatic ring, or two carbon groups. Hydrogen bonding, bond polarity, and resonance explain nomenclature, boiling points, solubility, acidity, and reaction patterns.

Alcohols, phenols, and ethers are distinguished by whether oxygen is bonded to saturated carbon, an aromatic ring, or two carbon groups. Hydrogen bonding, bond polarity, and resonance explain nomenclature, boiling points, solubility, acidity, and reaction patterns.

Commercial alcohols and safe application

Question 4

Which statement gives the sound Class XII chemistry for ‘Commercial alcohols and safe application’?

  1. (a)The same conclusion about commercial alcohols and safe application remains valid after changing the reagent, molecular structure, medium, or condition that controls the result.
  2. (b)Only the name of the substance is needed for commercial alcohols and safe application; equations, structures, stoichiometry, evidence, and conditions cannot change the answer.
  3. (c)Methanol and ethanol differ markedly in toxicity and uses. Industrial preparation, denaturation, fermentation, and oxidation must be linked to the correct compound and conditions. The two alcohols' chemistry cannot be swapped for each other.
  4. (d)For commercial alcohols and safe application, the relevant direction, trend, product ordering, or cause-and-effect relation is always the exact reverse of the governing rule.
Show answer

(c) Methanol and ethanol differ markedly in toxicity and uses. Industrial preparation, denaturation, fermentation, and oxidation must be linked to the correct compound and conditions. The two alcohols' chemistry cannot be swapped for each other.

Methanol and ethanol differ markedly in toxicity and uses. Industrial preparation, denaturation, fermentation, and oxidation must be linked to the correct compound and conditions rather than treated as interchangeable alcohol chemistry.

Question 5

Which principle should be retained when checking an inference about ‘Commercial alcohols and safe application’?

  1. (a)For commercial alcohols and safe application, the relevant direction, trend, product ordering, or cause-and-effect relation is always the exact reverse of the governing rule.
  2. (b)Methanol and ethanol differ markedly in toxicity and uses. Industrial preparation, denaturation, fermentation, and oxidation must be linked to the correct compound and conditions. The two alcohols' chemistry cannot be swapped for each other.
  3. (c)The same conclusion about commercial alcohols and safe application remains valid after changing the reagent, molecular structure, medium, or condition that controls the result.
  4. (d)Only the name of the substance is needed for commercial alcohols and safe application; equations, structures, stoichiometry, evidence, and conditions cannot change the answer.
Show answer

(b) Methanol and ethanol differ markedly in toxicity and uses. Industrial preparation, denaturation, fermentation, and oxidation must be linked to the correct compound and conditions. The two alcohols' chemistry cannot be swapped for each other.

Methanol and ethanol differ markedly in toxicity and uses. Industrial preparation, denaturation, fermentation, and oxidation must be linked to the correct compound and conditions rather than treated as interchangeable alcohol chemistry.

Question 6

Which statement survives a structure, equation, reagent, and condition audit for commercial alcohols and safe application?

  1. (a)Methanol and ethanol differ markedly in toxicity and uses. Industrial preparation, denaturation, fermentation, and oxidation must be linked to the correct compound and conditions. The two alcohols' chemistry cannot be swapped for each other.
  2. (b)The same conclusion about commercial alcohols and safe application remains valid after changing the reagent, molecular structure, medium, or condition that controls the result.
  3. (c)Only the name of the substance is needed for commercial alcohols and safe application; equations, structures, stoichiometry, evidence, and conditions cannot change the answer.
  4. (d)For commercial alcohols and safe application, the relevant direction, trend, product ordering, or cause-and-effect relation is always the exact reverse of the governing rule.
Show answer

(a) Methanol and ethanol differ markedly in toxicity and uses. Industrial preparation, denaturation, fermentation, and oxidation must be linked to the correct compound and conditions. The two alcohols' chemistry cannot be swapped for each other.

Methanol and ethanol differ markedly in toxicity and uses. Industrial preparation, denaturation, fermentation, and oxidation must be linked to the correct compound and conditions rather than treated as interchangeable alcohol chemistry.

Preparation of alcohols

Question 7

Which statement gives the sound Class XII chemistry for ‘Preparation of alcohols’?

  1. (a)Alcohols are prepared by hydration of alkenes, hydrolysis or reduction of suitable derivatives, and Grignard addition followed by hydrolysis. Carbon skeleton and reagent select primary, secondary, or tertiary product.
  2. (b)Only the name of the substance is needed for preparation of alcohols; equations, structures, stoichiometry, evidence, and conditions cannot change the answer.
  3. (c)For preparation of alcohols, the relevant direction, trend, product ordering, or cause-and-effect relation is always the exact reverse of the governing rule.
  4. (d)The same conclusion about preparation of alcohols remains valid after changing the reagent, molecular structure, medium, or condition that controls the result.
Show answer

(a) Alcohols are prepared by hydration of alkenes, hydrolysis or reduction of suitable derivatives, and Grignard addition followed by hydrolysis. Carbon skeleton and reagent select primary, secondary, or tertiary product.

Alcohols are prepared by hydration of alkenes, hydrolysis or reduction of suitable derivatives, and Grignard addition followed by hydrolysis. Carbon skeleton and reagent select primary, secondary, or tertiary product.

Question 8

Which principle should be retained when checking an inference about ‘Preparation of alcohols’?

  1. (a)For preparation of alcohols, the relevant direction, trend, product ordering, or cause-and-effect relation is always the exact reverse of the governing rule.
  2. (b)Only the name of the substance is needed for preparation of alcohols; equations, structures, stoichiometry, evidence, and conditions cannot change the answer.
  3. (c)The same conclusion about preparation of alcohols remains valid after changing the reagent, molecular structure, medium, or condition that controls the result.
  4. (d)Alcohols are prepared by hydration of alkenes, hydrolysis or reduction of suitable derivatives, and Grignard addition followed by hydrolysis. Carbon skeleton and reagent select primary, secondary, or tertiary product.
Show answer

(d) Alcohols are prepared by hydration of alkenes, hydrolysis or reduction of suitable derivatives, and Grignard addition followed by hydrolysis. Carbon skeleton and reagent select primary, secondary, or tertiary product.

Alcohols are prepared by hydration of alkenes, hydrolysis or reduction of suitable derivatives, and Grignard addition followed by hydrolysis. Carbon skeleton and reagent select primary, secondary, or tertiary product.

Question 9

Which statement correctly governs a new case involving preparation of alcohols?

  1. (a)Alcohols are prepared by hydration of alkenes, hydrolysis or reduction of suitable derivatives, and Grignard addition followed by hydrolysis. Carbon skeleton and reagent select primary, secondary, or tertiary product.
  2. (b)The same conclusion about preparation of alcohols remains valid after changing the reagent, molecular structure, medium, or condition that controls the result.
  3. (c)For preparation of alcohols, the relevant direction, trend, product ordering, or cause-and-effect relation is always the exact reverse of the governing rule.
  4. (d)Only the name of the substance is needed for preparation of alcohols; equations, structures, stoichiometry, evidence, and conditions cannot change the answer.
Show answer

(a) Alcohols are prepared by hydration of alkenes, hydrolysis or reduction of suitable derivatives, and Grignard addition followed by hydrolysis. Carbon skeleton and reagent select primary, secondary, or tertiary product.

Alcohols are prepared by hydration of alkenes, hydrolysis or reduction of suitable derivatives, and Grignard addition followed by hydrolysis. Carbon skeleton and reagent select primary, secondary, or tertiary product.

Phenol acidity, preparation, and electrophilic substitution

Question 10

Which statement gives the sound Class XII chemistry for ‘Phenol acidity, preparation, and electrophilic substitution’?

  1. (a)The same conclusion about phenol acidity, preparation, and electrophilic substitution remains valid after changing the reagent, molecular structure, medium, or condition that controls the result.
  2. (b)Only the name of the substance is needed for phenol acidity, preparation, and electrophilic substitution; equations, structures, stoichiometry, evidence, and conditions cannot change the answer.
  3. (c)For phenol acidity, preparation, and electrophilic substitution, the relevant direction, trend, product ordering, or cause-and-effect relation is always the exact reverse of the governing rule.
  4. (d)Phenol is more acidic than alcohols because phenoxide is resonance stabilised; substituents modify acidity. The activated aromatic ring undergoes mainly ortho/para substitution, Kolbe carboxylation, and Reimer–Tiemann formylation under their characteristic conditions.
Show answer

(d) Phenol is more acidic than alcohols because phenoxide is resonance stabilised; substituents modify acidity. The activated aromatic ring undergoes mainly ortho/para substitution, Kolbe carboxylation, and Reimer–Tiemann formylation under their characteristic conditions.

Phenol is more acidic than alcohols because phenoxide is resonance stabilised; substituents modify acidity. The activated aromatic ring undergoes mainly ortho/para substitution, Kolbe carboxylation, and Reimer–Tiemann formylation under their characteristic conditions.

Question 11

Which principle should be retained when checking an inference about ‘Phenol acidity, preparation, and electrophilic substitution’?

  1. (a)Only the name of the substance is needed for phenol acidity, preparation, and electrophilic substitution; equations, structures, stoichiometry, evidence, and conditions cannot change the answer.
  2. (b)Phenol is more acidic than alcohols because phenoxide is resonance stabilised; substituents modify acidity. The activated aromatic ring undergoes mainly ortho/para substitution, Kolbe carboxylation, and Reimer–Tiemann formylation under their characteristic conditions.
  3. (c)For phenol acidity, preparation, and electrophilic substitution, the relevant direction, trend, product ordering, or cause-and-effect relation is always the exact reverse of the governing rule.
  4. (d)The same conclusion about phenol acidity, preparation, and electrophilic substitution remains valid after changing the reagent, molecular structure, medium, or condition that controls the result.
Show answer

(b) Phenol is more acidic than alcohols because phenoxide is resonance stabilised; substituents modify acidity. The activated aromatic ring undergoes mainly ortho/para substitution, Kolbe carboxylation, and Reimer–Tiemann formylation under their characteristic conditions.

Phenol is more acidic than alcohols because phenoxide is resonance stabilised; substituents modify acidity. The activated aromatic ring undergoes mainly ortho/para substitution, Kolbe carboxylation, and Reimer–Tiemann formylation under their characteristic conditions.

Reactions and oxidation of alcohols

Question 12

Which statement gives the sound Class XII chemistry for ‘Reactions and oxidation of alcohols’?

  1. (a)Only the name of the substance is needed for reactions and oxidation of alcohols; equations, structures, stoichiometry, evidence, and conditions cannot change the answer.
  2. (b)The same conclusion about reactions and oxidation of alcohols remains valid after changing the reagent, molecular structure, medium, or condition that controls the result.
  3. (c)Alcohol reactions include O–H cleavage, conversion to haloalkanes, dehydration, esterification, and oxidation. Product and mechanism depend on alcohol class, reagent, temperature, and rearrangement tendency.
  4. (d)For reactions and oxidation of alcohols, the relevant direction, trend, product ordering, or cause-and-effect relation is always the exact reverse of the governing rule.
Show answer

(c) Alcohol reactions include O–H cleavage, conversion to haloalkanes, dehydration, esterification, and oxidation. Product and mechanism depend on alcohol class, reagent, temperature, and rearrangement tendency.

Alcohol reactions include O–H cleavage, conversion to haloalkanes, dehydration, esterification, and oxidation. Product and mechanism depend on alcohol class, reagent, temperature, and rearrangement tendency.

Question 13

Which principle should be retained when checking an inference about ‘Reactions and oxidation of alcohols’?

  1. (a)For reactions and oxidation of alcohols, the relevant direction, trend, product ordering, or cause-and-effect relation is always the exact reverse of the governing rule.
  2. (b)Alcohol reactions include O–H cleavage, conversion to haloalkanes, dehydration, esterification, and oxidation. Product and mechanism depend on alcohol class, reagent, temperature, and rearrangement tendency.
  3. (c)The same conclusion about reactions and oxidation of alcohols remains valid after changing the reagent, molecular structure, medium, or condition that controls the result.
  4. (d)Only the name of the substance is needed for reactions and oxidation of alcohols; equations, structures, stoichiometry, evidence, and conditions cannot change the answer.
Show answer

(b) Alcohol reactions include O–H cleavage, conversion to haloalkanes, dehydration, esterification, and oxidation. Product and mechanism depend on alcohol class, reagent, temperature, and rearrangement tendency.

Alcohol reactions include O–H cleavage, conversion to haloalkanes, dehydration, esterification, and oxidation. Product and mechanism depend on alcohol class, reagent, temperature, and rearrangement tendency.

Ether preparation and cleavage

Question 14

Which statement gives the sound Class XII chemistry for ‘Ether preparation and cleavage’?

  1. (a)The same conclusion about ether preparation and cleavage remains valid after changing the reagent, molecular structure, medium, or condition that controls the result.
  2. (b)Only the name of the substance is needed for ether preparation and cleavage; equations, structures, stoichiometry, evidence, and conditions cannot change the answer.
  3. (c)For ether preparation and cleavage, the relevant direction, trend, product ordering, or cause-and-effect relation is always the exact reverse of the governing rule.
  4. (d)Williamson synthesis is an SN2 reaction and works best with primary alkyl halides. Ethers are relatively inert but cleave with concentrated HI or HBr; in aryl–alkyl ethers cleavage occurs at the alkyl O–C bond because the aryl bond resists SN2.
Show answer

(d) Williamson synthesis is an SN2 reaction and works best with primary alkyl halides. Ethers are relatively inert but cleave with concentrated HI or HBr; in aryl–alkyl ethers cleavage occurs at the alkyl O–C bond because the aryl bond resists SN2.

Williamson synthesis is an SN2 reaction and works best with primary alkyl halides. Ethers are relatively inert but cleave with concentrated HI or HBr; in aryl–alkyl ethers cleavage occurs at the alkyl O–C bond because the aryl bond resists SN2.

Question 15

Which principle should be retained when checking an inference about ‘Ether preparation and cleavage’?

  1. (a)Williamson synthesis is an SN2 reaction and works best with primary alkyl halides. Ethers are relatively inert but cleave with concentrated HI or HBr; in aryl–alkyl ethers cleavage occurs at the alkyl O–C bond because the aryl bond resists SN2.
  2. (b)For ether preparation and cleavage, the relevant direction, trend, product ordering, or cause-and-effect relation is always the exact reverse of the governing rule.
  3. (c)Only the name of the substance is needed for ether preparation and cleavage; equations, structures, stoichiometry, evidence, and conditions cannot change the answer.
  4. (d)The same conclusion about ether preparation and cleavage remains valid after changing the reagent, molecular structure, medium, or condition that controls the result.
Show answer

(a) Williamson synthesis is an SN2 reaction and works best with primary alkyl halides. Ethers are relatively inert but cleave with concentrated HI or HBr; in aryl–alkyl ethers cleavage occurs at the alkyl O–C bond because the aryl bond resists SN2.

Williamson synthesis is an SN2 reaction and works best with primary alkyl halides. Ethers are relatively inert but cleave with concentrated HI or HBr; in aryl–alkyl ethers cleavage occurs at the alkyl O–C bond because the aryl bond resists SN2.

Common misconception in Alcohols, Phenols and Ethers

Open full misconception guide →

Is phenol as weak an acid as ethanol?

Wrong

Phenol and ethanol are equally acidic because both contain an –OH group.

Why it feels right. The structures share the group that loses a proton.

Right

The stability of the conjugate base helps determine acidity.

Worked example

Phenol
Loses H⁺→Phenoxide→Charge delocalised
Ethanol
Loses H⁺→Ethoxide→Charge mainly on O
Compare the conjugate bases. Phenoxide can spread negative charge through the ring.
  1. Phenoxide spreads some negative charge through the ring.
  2. Ethoxide lacks this resonance stabilisation, so phenol gives up its proton more readily than ethanol.