CBSE Previous year questions (2019-2023)
Alcohols, Phenols & Ethers
Multiple Choice Questions (1 mark)
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1. |
In the reaction (a) 10< 20< 30(b) 10> 30> 20 (c) 10> 20> 30(d) 30> 10> 20 |
(2023) |
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2. |
Aspirin is obtained by the acetylation of which of the following compounds ? (a) Salicylaldehyde (b) Salicylic acid (c) Acetyl salicylic acid (d) Phenol |
(2023) |
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3. |
Sodium phenoxide when heated with CO2 under pressure, followed by acidification, yields : (a) Sodium benzoate (b) Salicylic acid (c) Salicylaldehyde (d) Benzoic acid |
(2023) |
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4. |
Which of the following alcohols will not undergo oxidation ? (a) Butanol (b) Butan-2-ol (c) 2-Methylbutan-2-ol (d) 3-Methylbutan-2-ol |
(2023) |
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5. |
Which of the following alcohols will not undergo oxidation ? (a) Butanol (b) Butan-2-ol (c) 2-Methylbutan-2-ol (d) 3-Methylbutan-2-ol
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(2023) |
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6. |
When diethyl ether is heated with excess of HI, it produces : (a) ethanol (b) iodoform (c) methyl iodide (d) ethyl iodide |
(2023) |
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7. |
Which of the following alkenes on acid catalysed hydration gives a tertiary alcohol ? (a) 2-Butene (b) 2-Methylpropene (c) Propene (d) 1-Butene |
(2023) |
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8. |
Which of the following reactions are feasible ? (a) CH3CH2Br + Na+O-C(CH3)3 ----Ã CH3CH2–O – C (CH3)3 (b) (CH3)3 C – Cl + Na+O-CH2CH3 ---Ã CH3CH2 – O – C(CH3)3 (c) Both (a) and (b) (d) Neither (a) nor (b) |
(2023) |
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9. |
Choose the compound which is more acidic than phenol : (a) o-nitrophenol (b) ethanol (c) o-methylphenol (d) o-methoxyphenol |
2023 (C) |
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10. |
What would be the major product of the given reaction ?  (a) Ethanal (b) Propanol (c) Ethanol (d) Propanal |
2023 (C) |
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11. |
Which of the following, on reaction with CH3MgI and subsequent hydrolysis, will form a primary alcohol ? (a) HCHO (b) CH3CHO (c) CH3COCH3 (d) Benzaldehyde |
2023 (B) |
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12. |
Which of the following compound is called Picric acid ? (a) p-Nitrophenol (b) 2,4-Dinitrophenol (c) 2,4,6-Trinitrophenol (d) 2,6-Dinitrophenol |
2023 (B) |
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13. |
The correct IUPAC name of  (A) tert-butyl alcohol (B) 2,2-Dimethylpropanol (C) 2-Methylbutan-2-ol (D) 3-Methylbutan-3-ol |
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14. |
Arrange the following in increasing order of their boiling point : CH3CH2OH, CH3CHO, CH3 – O – CH3 |
2019 |
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15. |
Arrange the following in increasing order of their acidic character : Ethanol, Phenol, Water |
2019 |
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For following questions, two statements are given one labelled as Assertion (A) and the other labelled as Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below. (a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A). (b) Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A). (c) Assertion (A) is true, but Reason (R) is false. (d) Assertion (A) is false, but Reason (R) is true. |
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1. |
Assertion (A) : The boiling point of ethanol is lower than that of diethyl ether. Reason (R) : In ethanol, the molecules are associated due to intermolecular hydrogen bonding, whereas in diethyl ether it is not possible. |
2023 (B) |
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2. |
Assertion (A) : Phenol gives 2,4,6-trinitrophenol on treatment with concentrated HNO3 and concentrated H2SO4. Reason (R) : OH group in phenol is m-directing. |
2023 (C) |
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3. |
Assertion (A) : Hydrolysis of an ester in acidic medium is a second order reaction. Reason (R) : For a complex reaction, order is given by the slowest step. |
2023 (B) |
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4. |
Assertion (A) : Ortho-nitrophenol is more acidic than phenol Reason (R) : Nitro group is electron donating group and therefore stabilizes ortho-nitrophenoxide ion. |
2021 (C) |
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5. |
Assertion (A) : p-nitrophenol is more acidic than phenol
Reason (R) : Nitro group is electron withdrawing group and stabilizes p-nitrophenoxide ion. |
2021 (B) |
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6. |
Assertion (A) : o-nitrophenol is a weaker acid than p-nitrophenol. Reason (R) : Intramolecular hydrogen bonding makes ortho isomerweaker than para isomer. |
2020 |
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7. |
Assertion (A) : Phenol is more acidic than p-methylphenol.
Reason (R) : The presence of an electron releasing group in p-methylphenol makes it less acidic. |
2020 |
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8. |
Assertion (A) : The C – O – H bond angle in alcohols is slightly less than the tetrahedral angle. Reason (R) : This is due to the repulsive interaction between the twolone electron pairs on oxygen. |
2020 |
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9. |
Assertion (A) : (CH3)3 C–O–CH3 gives (CH3)3 C–I and CH3OH on treatment with HI. Reason (R) : The reaction occurs by SN1 mechanism. |
2020 |
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10. |
Assertion (A) : The C-O-C bond angle in ethers is slightly less thantetrahedral angle. Reason (R) : Due to the repulsive interaction between the two alkylgroups in ethers. |
2020 |
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11. |
Assertion (A) : Ortho and para-nitrophenols can be separated by steam distillation. Reason (R) : Ortho isomer associates through intermolecular hydrogen bonding while Para isomer associates through intramolecular hydrogen bonding. |
2020 |
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12. |
Assertion (A) : p-nitro phenol is a stronger acid than p-cresol. Reason (R) : NO2 group is an electron releasing group while– CH3 group is electron withdrawing in nature. |
2020 |
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13. |
Assertion (A) : Phenols do not react with phosphorus halideswhile alcohols do react. Reason (R) : In phenols C – O bond has partial double bond character due to resonance while it is not so in alcohols. |
2020 (B) |
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14. |
Assertion (A) : Alcohols have higher boiling point than alkanes of comparable molecular mass. Reason (R) : Alcohols have intramolecular hydrogen bond. |
2020 (C) |
Very Short Answer type questions (2 marks)
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1. |
(a) Account for the following : (i) Phenol is a stronger acid than an alcohol. (ii) The boiling point of alcohols decreases with increase in branching of alkyl chain. OR (b) (i) Write the mechanism of the following reaction :  (ii) Write the equation involved in Reimer-Tiemann reaction. |
(2023) |
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2. |
(a) Predict the products of the following reactions :  OR (b) Give reasons for the following : (i) p-nitrophenol is more acidic than p-methylphenol. (ii) (CH3)3C Br on reaction with NaOCH3 gives alkene as the main product and not an ether. |
(2023) |
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3. |
 Identify ‘A’ and ‘B’ in the above reaction. |
(2023) |
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4. |
(a) Account for the following : (i) Phenol is a stronger acid than an alcohol. (ii) The boiling point of alcohols decreases with increase in branching of alkyl chain. OR (b) (i) Write the mechanism of the following reaction :  (ii) Write the equation involved in Reimer-Tiemann reaction. |
(2023) |
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5. |
Give the structures and IUPAC name of the products expected from the following reactions : (a) Reaction of methanal with (b) Reaction of phenol with Br2 (aq). |
(2023) |
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6. |
Write the structures and IUPAC names of the products expected from the following reactions : (a) Reaction of methanal with (CH3)2CHMgBr followed by hydrolysis. (b) Reaction of phenol with conc. HNO3 . |
(2023) |
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7. |
Show how you will synthesise :
2.
 from methanal using a suitable Grignard reagent. |
(2023) |
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8. |
For the pair phenol and cyclohexanol, answer the following : (a) Why is phenol more acidic than cyclohexanol ? (b) Give one chemical test to distinguish between the two. |
(2023) |
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9. |
Write the mechanism of the following reaction :  |
(2023) |
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10. |
Which of the following is an appropriate set of reactants for the preparation of 1-methoxy-4-nitrobenzene and why ?  |
(2023) |
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11. |
Write the mechanism of acid dehydration of ethanol to yield ethene. |
(2023) |
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12. |
Write the chemical equation involved in the following reactions : (a) Reimer-Tiemann reaction (b) Acetylation of Salicylic acid |
(2023) |
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13. |
Write the chemical equation involved in the following : (a) Kolbe’s reaction (b) Williamson synthesis |
(2023) |
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14. |
Write the chemical equation involved in the following reactions : (a) Reimer-Tiemann reaction (b) Acetylation of Salicylic acid |
(2023) |
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15. |
Write the chemical equation involved in : (a) Reimer-Tiemann reaction (b) Williamson ether synthesis |
2023 (B) |
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16. |
Or
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2021 (C) |
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17. |
Write equations of the following reaction:
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2021 (C) |
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18. |
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2021 (C) |
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19. |
Write the name of reagent (s) used in the following reactions:  |
2020 |
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20. |
Give reasons for the following : (a) Bond angle angle.
(b) C – OH bond length in CH3OH is slightly more than the C – OH bond length in phenol. |
2020 |
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21. |
How will you convert : (a) Phenol to Picric acid (b) Ethanal to Propan-2-ol |
2020 |
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22. |
What happens when (a) Phenol reacts with Conc. HNO3 ? (b) Ethyl chloride reacts with NaOC2H5 ? Write the chemical equations involved in the above reactions. |
2019 |
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23. |
Define with equation : (a) Riemer-Tiemann Reaction (b) Williamson’s Synthesis |
2019 |
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24. |
An aromatic compound ‘A’ on treatment with CHCl3 and KOH gives two compounds, both of which give same product ‘B’ when distilled with Zinc dust. Oxidation of ‘B’ gives ‘C’ with molecular formula C7H6O2. Sodium salt of ‘C’ on heating with soda lime gives ‘D’ which may also be obtained by distilling ‘A’ with Zinc dust. Identify ‘A’, ‘B’, ‘C’ and ‘D’. OR How do you convert the following : (a) Phenol to Toluene (b) Ethanol to Ethanal |
2019 |
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25. |
Predict the major product obtained when t-butyl bromide reacts with sodium methoxide. Also, give its IUPAC name. OR (a) Show the chemical reaction with bond movements and arrows for the nucleophilic attack of water on carbocation in acid catalysed hydration of alkenes.
(b) Give IUPAC name for the following :  |
2019 (C) |
Short Answer type questions (3 marks)
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1. |
How do you convert the following : (Any three) (a) Phenol to picric acid (b) Propanone to 2-Methylpropan-2-ol (c) Phenol to anisole (d) Propene to Propan-1-ol |
(2023) |
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2. |
Complete the following reactions :  |
(2023) |
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3. |
How do you convert the following : (Any three) (a) Phenol to 2-Hydroxybenzaldehyde (b) Anisole to 2-Methoxyacetophenone (c) Propene to Propan-2-ol (d) Ethanol to Ethanal |
(2023) |
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4. |
(a) Write the mechanism of the following reaction :
 (b) Write the equation of the reaction for the preparation of phenol from cumene. |
(2023) |
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5. |
(a) Write the mechanism of the following reaction : 
(b) Write the structures of the products obtained by heating
 with conc. HI. |
(2023) |
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6. |
(a) (i) Why is the C – O bond length in phenols less than that in methanol ? (ii) Arrange the following in order of increasing boiling point : Ethoxyethane, Butanal, Butanol, n-butane (iii) How can phenol be prepared from anisole ? Give reaction. OR (b) (i) Give mechanism of the following reaction :  (ii) Illustrate hydroboration – oxidation reaction with an example. |
(2023) |
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7. |
(a) (i) Write hydroboration-oxidation reaction with an example. (ii) Write the products of the following reaction :  (iii) Why is p-nitrophenol more acidic than phenol ? OR (b) (i) What happens when phenol reacts with (1) Conc. HNO3, and (2) CHCl3 in presence of aqueous NaOH followed byacidification ? Write equations only. (ii) Why does the reaction of CH3ONa with (CH3)3C-Br give 2-methylpropene and not (CH3)3C-OCH3 ? |
(2023) |
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8. |
(a) (i) Write the mechanism of the following reaction :  (ii) Why ortho-nitrophenol is steam volatile while para-nitrophenol is not ? OR (b) What happens when
(i) Anisole is treated with CH3Cl/anhydrous AlCl3 ? (ii) Phenol is oxidised with Na2Cr2O7/H+ ? (iii) (CH3)3 C – OH is heated with Cu/573 K ? Write chemical equation in support of your answer. |
(2023) |
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9. |
(a) How do you convert the following : (i) Phenol to Benzene (ii) Ethanol to propan-2-ol (iii) Anisole to 2-methoxyacetophenone OR
(b) (i) How will you distinguish between primary, secondary and tertiary alcohol by Lucas reagent ? (ii) Why is o-nitrophenol steam volatile while p-nitrophenol is not ? |
(2023) |
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10. |
Write the chemical equation for the following : (a) Hydration of propene in presence of an acid. (b) Reaction between Ethyl bromide and C2H5ONa. (c) Reaction between Dimethyl ether and Hydrogen iodide. |
2023 (C) |
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11. |
Write the chemical equation for the following : (a) Oxidation of secondary alcohol to ketone by chromic anhydride (CrO3). (b) Reaction of anisole with a mixture of concentrated sulphuric acid and nitric acid. (c) Reaction of HI with 1-propoxypropane. |
2023 (C) |
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12. |
Write chemical equations for the following : (a) Reaction between phenol and Zn dust. (b) Reaction of anisole with bromine in ethanoic acid. (c) Reaction between methoxybenzene and HI. |
2023 (C) |
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13.
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Write the major product(s) of the following reactions :  |
2020 |
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14. |
(a) Write the mechanism of the following reaction :  (b) Write the preparation of phenol from cumene. OR How can you convert the following : (i) Sodium phenoxide to o-hydroxybenzoic acid (ii) Acetone to propene (iii) Phenol to chlorobenzene |
2020 |
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15. |
Write the product(s) of the following reactions : 
 (b) Write the equation for the preparation of 2-methyl-2- methoxypropane by Williamson synthesis. |
2020 |
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16. |
Give the structures of final products expected from the following reactions : (i) Hydroboration of propene followed by oxidation with H2O2 in alkaline medium. (ii) Dehydration of (CH3)3C–OH by heating it with 20% H3PO4 at 358 K. (iii) Heating of OR
How can you convert the following ? (i) Phenol to o-hydroxybenzaldehyde. (ii) Methanal to ethanol (iii) Phenol to phenyl ethanoate. |
2020 |
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17. |
Write the structure of the main products formed in the following reactions 
(a) Carry out the following conversions : (i) Propene to propan-2-ol (ii) Benzyl chloride to benzyl alcohol (b) Arrange the following compounds in increasing order of their acidic strength : 4-Methylphenol, Phenol, 4-Nitrophenol |
2020 (C) |
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18. |
What happens when (a) Salicylic acid is treated with (CH3CO)2O/H+ ? (b) Phenol is oxidised with Na2Cr2O7/H+ ? (c) Anisole is treated with CH3Cl/anhydrous AlCl3 ? Write chemical equation in support of your answer. |
2019 |
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19. |
What happens when (a) Sodium phenoxide is treated with CH3Cl ? (b) CH2 = CH – CH2 – OH is oxidised by PCC ? (c) Phenol is treated with CH3COCl/anhydrous AlCl3 ? Write chemical equations in support of your answer. |
2019 |
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20. |
(a) Butan-1-ol has a higher boiling point than diethyl ether. Why ? (b) Write the mechanism of the following reaction :  |
2019 |
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21. |
(a) How will you synthesise the following alcohol from appropriate alkene :
 |
2019 |
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22. |
Give one chemical test to distinguish between the following : (a) Phenol and 1-propanol (b) Ethanol and dimethyl ether
(c) 1-propanol and 2-Methyl-2-propanol OR Write the products of the following reactions :  |
2019 |
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23. |
(a) Show how you will synthesise the following alcohol prepared by the reaction of a suitable Grignard reagent on methanal ? (b)Write the mechanism of the following reaction :  |
2019 |
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24. |
(a) How will you convert the following : (i) Phenol to benzoquinone (ii) Propanone to 2-methyl propan-2-ol (b) Why does propanol have higher boiling point than that of butane ? |
2019 (C) |
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25. |
(a) How will you convert the following : (i) Phenol to benzene (ii) Propene to propanol (b) Why is ortho-nitrophenol more acidic than ortho-methoxyphenol ? |
2019 (C) |
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26. |
(a) How will you convert the following : (i) Ethanal to propan-2-ol (ii) Phenol to 2-hydroxyacetophenone (b) Why is phenol more acidic than ethanol ? |
2019 (C) |
Case based questions. (4 marks)
The following questions are case-based questions. Each question hasan internal choice and carries 4 (1 + 1 + 2) marks each. Read the casecarefully and answer the questions that follow.
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1. |
Alcohols have higher boiling points than other classes of compounds, namely hydrocarbons, ethers and haloalkanes ofcomparable molecular masses. Alcohols and phenols are acidic in nature. Electron withdrawing groups in phenol increase its acidic strength and electron releasing groups decrease it. Alcohols may be prepared by acid catalysed hydration of alkenes, hydroboration-oxidation reaction, from carbonyl compounds by catalytic reduction and the action of Grignard reagents. Answer the following : (i) Why is o-nitrophenol more acidic than o-methoxyphenol ? (ii) Why does propanol have higher boiling point thanpropane ? (iii) Name the reagents used in the following reactions : (1) Oxidation of primary alcohol to aldehyde (2) Dehydration of propan-2-ol to propene OR (iii) How do you convert 2x1=2 (1) Prop-1-ene to propan-1-ol ? (2) Acetone to propan-2-ol ? |
2023 (B) |
Long Answer type questions (5 marks)
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1. |
(a) (i) Carry out the following conversions : (1) Ethanal to But-2-en-1-al (2) Propanoic acid to 2-chloropropanoic acid (ii) An alkene with molecular formula C5H10 on ozonolysis gives a mixture of two compound ‘B’ and ‘C’. Compound ‘B’ gives positive Fehling test and also reacts with iodine and NaOH solution. Compound ‘C’ does not give Fehling solution test but forms iodoform. Identify the compounds ‘A’, ‘B’ and ‘C’. 2+3=5 OR (b) (i) Distinguish with a suitable chemical test : (1) CH3COCH2CH3 and CH3CH2CH2CHO (2) Ethanal and Ethanoic acid (ii) Write the structure of oxime of acetone. (iii) Identify A to D.  |
(2023) |
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2. |
(a) Out of t-butyl alcohol and n-butanol, which one will undergo acidcatalyzed dehydration faster and why ? (b) Carry out the following conversions : (i) Phenol to Salicylaldehyde (ii) t-butylchloride to t-butyl ethyl ether (iii) Propene to Propanol OR
(a) Give the mechanism for the formation of ethanol from ethene. (b) Predict the reagent for carrying out the following conversions : (i) Phenol to benzoquinone (ii) Anisole to p-bromoanisole (iii) Phenol to 2,4,6-tribromophenol |
2020 |
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3. |
(a) Write the mechanism for dehydration of Ethanol (underacidic conditions) at 443 K. (b) How will you convert (i) Phenol to Toluene, and (ii) Ethanal to Propan-2-ol ? OR An organic compound (A) having molecular formula C6H6Ogives acharacteristic colour with aqueous ferric chloridesolution. When (A) is treated with CO2 and NaOH at 400 Kunder pressure, (B) is obtained. The compound (B) onacidification gives compound (C) which reacts with acetylchloride to form (D) which is a popular pain killer. Deduce thestructures of A, B, C and D and write reactions. |
2020 (C) |
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4. |
(a) How do you convert the following : (i) Phenol to Anisole (ii) Ethanol to Propan-2-ol (b) Write mechanism of the following reaction : 
(c) Why phenol undergoes electrophilic substitution more easily than benzene ? OR
(a) Account for the following : (i) o-nitrophenol is more steam volatile than p-nitrophenol. (ii) t-butyl chloride on heating with sodium methoxide gives 2-methylpropene instead of t-butylmethylether. (b) Write the reaction involved in the following : (i) Reimer-Tiemann reaction (ii) Friedal-Crafts Alkylation of Phenol (c) Give simple chemical test to distinguish between Ethanol and Phenol. |
2019 |
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5. |
(a) Give equations of the following reactions : (i) Phenol is treated with conc. HNO3. (ii) Propene is treated with B2H6 followed by H2O2/OH–. (iii) Sodium t-butoxide is treated with CH3Cl. (b) How will you distinguish between butan-1-ol and butan-2-ol ? (c) Arrange the following in increasing order of acidity : Phenol, ethanol, water |
2019 |
Prepared By:
Satyam Kumar Nigam
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