Chapter-11 Alcohols, Phenols and Ethers

Match the items of column I with items of column II.
Column I Column II
(i) Methanol (a) Conversion of phenol to
o-hydroxysalicylic acid 

(ii) Kolbe’s reaction (b) Ethyl alcohol
(iii) Williamson’s synthesis (c) Conversion of phenol to
salicylaldehyde
(iv) Conversion of 2° alcohol to ketone (d) Wood spirit
(v) Reimer-Tiemann reaction (e) Heated copper at 573K
(vi) Fermentation (f) Reaction of alkyl halide with
sodium alkoxide

Match the  items of column I with items of column II.
Column I                                                           Column II
(i) Antifreeze used in car engine                            (a) Neutral ferric chloride
(ii) Solvent used in perfumes                                (b) Glycerol
(iii) Starting material for picric acid                        (c) Methanol
(iv) Wood spirit                                                 (d) Phenol
(v) Reagent used for detection of                          (e) Ethleneglycol
phenolic group
(vi) By product of soap industry                           (f) Ethanol
used in cosmetics

Arrange water, ethanol and phenol in increasing order of acidity and give
reason for your answer.

The carbon-oxygen bond in phenol is slightly stronger than that in methanol.
Why?

Explain why alcohols and ethers of comparable molecular mass have different
boiling points?

Explain why p-nitrophenol is more acidic than phenol.

Explain why low molecular mass alcohols are soluble in water.

Why is the C—O—H bond angle in alcohols slightly less than the tetrahedral
angle whereas the C—O—C bond angle in ether is slightly greater?

Ethers can be prepared by Williamson synthesis in which an alkyl halide is
reacted with sodium alkoxide. Di-tert-butyl ether can’t be prepared by this
method. Explain.

Dipole moment of phenol is smaller than that of methanol. Why?

In Kolbe’s reaction, instead of phenol, phenoxide ion is treated with carbon
dioxide. Why?

Nitration is an example of aromatic electrophilic substitution and its rate
depends upon the group already present in the benzene ring. Out of benzene
and phenol, which one is more easily nitrated and why?

Write steps to carry out the conversion of phenol to aspirin.

Explain why is O==C==O nonpolar while R—O—R is polar.

Preparation of alcohols from alkenes involves the electrophilic attack on alkene
carbon atom. Explain its mechanism

Explain why nucleophilic substitution reactions are not very common in phenols.

Explain why is OH group in phenols more strongly held as compared to OH
group in alcohols.

How can propan-2-one be converted into tert- butyl alcohol?

Name the enzymes and write the reactions involved in the preparation of ethanol
from sucrose by fermentation.

What happens when benzene diazonium chloride is heated with water?

Alcohols react with active metals e.g. Na, K etc. to give corresponding alkoxides.
Write down the decreasing order of reactivity of sodium metal towards primary,
secondary and tertiary alcohols.

Arrange the following compounds in increasing order of acidity and give a
suitable explanation.
Phenol, o-nitrophenol, o-cresol

When phenol is treated with bromine water, white precipitate is obtained. Give
the structure and the name of the compound formed.

Out of o-nitrophenol and o-cresol which is more acidic?

Out of o-nitrophenol and p-nitrophenol, which is more volatile? Explain.

Suggest a reagent for conversion of ethanol to ethanoic acid.

Suggest a reagent for conversion of ethanol to ethanal.

Out of 2-chloroethanol and ethanol which is more acidic and why?

What is denatured alcohol?

Name the factors responsible for the solubility of alcohols in water.

What is the structure and IUPAC name of glycerol?

Preparation of ethers by acid dehydration of secondry or 30

alcohols is not a suitable method?

Phenols do not give protonation reactions  readily. Why?

Ortho‐ nitrophenol is more acidic than ortho –methoxy phenol ? why?

Explain why propanol has higher boiling point than that of the hydrocarbon, butane?

Alcohols are comparatively more soluble in water than hydrocarbons of comparable molecular masses. Explain this fact. 

While separating a mixture of ortho and para nitrophenols by steam distillation, name the isomer which will be steam volatile. Give reason.

Explain why is ortho nitrophenol more acidic than ortho methoxyphenol?

Preparation of ethers by acid dehydration of secondary or tertiary alcohols is not a suitable method. Give reason.

What is meant by hydroboration‐oxidation reaction? Illustrate it with an example .

 Give the equations of reactions for the preparation of phenol from

cumene.

Write chemical reaction for the preparation of phenol from chlorobenzene.

  How is aspirin (Acetylsalicylic acid) prepared from salicylic acid?  

Which out of propan-1-ol and propan-2-ol is stronger acid? 

What is denaturation of an alcohol?

Give IUPAC name of CH3OCH2OCH3

Diethyl ether does not react with sodium. Explain.

Give two reactions that show the acidic nature of phenol. Compare acidity of phenol with that of ethanol.

How does phenol react with dilute and conc. HNO3 ?

How does phenol react with Br2 in CS2 and Bromine water? 

How do you account for the fact that unlike phenol, 2, 4- dinitrophenol and 2, 4, 6-trinitrophenol are soluble in aqueous solution of sodium carbonate?

( i) Why is the Dipole moment of methanol higher than that of phenol? (ii) . Explain why phenols do not undergo substitution of the

–OH group like alcohols.

Account for the following

Answer the following

Give reasons:

i)Nitration of phenol gives ortho- and para- products only.

ii)Why do alcohols have higher boiling points than the haloalkanes of the same molecular mass?

Account for the following:

i) Phenols has a smaller dipole moment than methanol

ii) Phenols do not give protonation reactions readily.

Explain the fact that in aryl alkyl ethers

(i) The alkoxy group activates the benzene ring towards electrophilic

substitution and

(ii) It directs the incoming substituents to ortho and para positions in

benzene ring.

How are primary, secondary and tertiary alcohols prepared from Grignard Reagents?

Give the equations of oxidation of primary, secondary and tertiary alcohols by Cu at 573 K.

Give equations of the following reactions:

(i) Oxidation of propan-1-ol with alkaline KMnO4 solution.

(ii) Bromine in CS2 with phenol. (iii) Dilute HNO3 with phenol. 

Show how will you synthesize:

(i)    1-phenylethanol from a suitable alkene.

(ii)    (ii) cyclohexylmethanol using an alkyl halide by an SN2 reaction. (iii)  (iii) pentan-1-ol using a suitable alkyl halide?

How are the following conversions carried out?

(i)Propene → Propan-2-ol

(ii) Benzyl chloride → Benzyl alcohol

(iii) Ethyl magnesium chloride → Propan-1-ol.

Name the reagents used in the following reactions:

(i) Oxidation of a primary alcohol to carboxylic acid.

  (ii) Oxidation of a primary alcohol to aldehyde.

(iii) Bromination of phenol to 2,4,6-tribromophenol. 

How is 1-propoxypropane synthesised from propan-1-ol? Write mechanism of this reaction.

Write the equation of the reaction of hydrogen iodide with:

(i)     1-propoxypropane (ii) Methoxybenzene and (iii) Benzyl ethyl ether

When 3-methylbutan-2-ol is treated with HBr, the following reaction takes

place:

Give a mechanism for this reaction.

(Hint : The secondary carbocation formed in step II rearranges to a more

stable tertiary carbocation by a hydride ion shift from 3rd carbon atom.

Show how would you synthesise the following alcohols from appropriate alkenes?

(i)

(ii)

(iii)

(iv)

Write equations of the following reactions:

(i) Friedel-Crafts reaction-alkylation of anisole.

(ii) Nitration of anisole.

(iii) Bromination of anisole in ethanoic acid medium.

(iv) Friedel-Craft's acetylation of anisole.

Write the mechanism of the reaction of HI with methoxymethane.

Explain the fact that in aryl alkyl ethers

(i) The alkoxy group activates the benzene ring towards electrophilic substitution and

(ii) It directs the incoming substituents to ortho and para positions in benzene ring.

Write the equation of the reaction of hydrogen iodide with:

(i) 1-propoxypropane

(ii) Methoxybenzene and

(iii) Benzyl ethyl ether

Preparation of ethers by acid dehydration of secondary or tertiary alcohols is not a suitable method. Give reason.

How is 1-propoxypropane synthesised from propan-1-ol? Write mechanism of this reaction.

Illustrate with examples the limitations of Williamson synthesis for the preparation of certain types of ethers.

Write the names of reagents and equations for the preparation of the following ethers by Williamson's synthesis:

(i) 1-Propoxypropane

(ii) Ethoxybenzene

(iii) 2-Methoxy-2-methylpropane

(iv) 1-Methoxyethane

Give IUPAC names of the following ethers:

(i)

(ii)

(iii)

(iv)

(v)

(vi)

Give reason for the higher boiling point of ethanol in comparison to methoxymethane.

Name the reagents used in the following reactions:

(i) Oxidation of a primary alcohol to carboxylic acid.

(ii) Oxidation of a primary alcohol to aldehyde.

(iii) Bromination of phenol to 2,4,6-tribromophenol.

(iv) Benzyl alcohol to benzoic acid.

(v) Dehydration of propan-2-ol to propene.

(vi) Butan-2-one to butan-2-ol.

How are the following conversions carried out?

(i) Propene → Propan-2-ol

(ii) Benzyl chloride → Benzyl alcohol

(iii) Ethyl magnesium chloride → Propan-1-ol.

(iv) Methyl magnesium bromide → 2-Methylpropan-2-ol.

Write the mechanism of acid-catalysed dehydration of ethanol to yield ethene.

Explain the following with an example.

(i) Kolbe's reaction.

(ii) Reimer-Tiemann reaction.

(iii) Williamson ether synthesis.

(iv) Unsymmetrical ether.

Give equations of the following reactions:

(i) Oxidation of propan-1-ol with alkaline KMnO₄ solution.

(ii) Bromine in CS₂ with phenol.

(iii) Dilute HNO₃ with phenol.

(iv) Treating phenol with chloroform in presence of aqueous NaOH.

Explain how does the -OH group attached to a carbon of benzene ring activate it towards electrophilic substitution?

Explain why is ortho nitrophenol more acidic than ortho methoxyphenol?

Give two reactions that show the acidic nature of phenol. Compare acidity of phenol with that of ethanol.

Show how will you synthesize:

(i) 1-phenylethanol from a suitable alkene.

(ii) cyclohexylmethanol using an alkyl halide by an S_N2 reaction.

(iii) pentan-1-ol using a suitable alkyl halide?

You are given benzene, conc. H₂SO₄ and NaOH. Write the equations for the preparation of phenol using these reagents.

Write the mechanism of hydration of ethene to yield ethanol.

Write chemical reaction for the preparation of phenol from chlorobenzene.

Give the equations of reactions for the preparation of phenol from cumene.

While separating a mixture of ortho and para nitrophenols by steam distillation, name the isomer which will be steam volatile. Give reason.

Give the structures and IUPAC names of monohydric phenols of molecular formula, C₇H₈O.

What is meant by hydroboration-oxidation reaction? Illustrate it with an example.

Alcohols are comparatively more soluble in water than hydrocarbons of comparable molecular masses. Explain this fact.

Explain why propanol has higher boiling point than that of the hydrocarbon, butane?

(i) Draw the structures of all isomeric alcohols of molecular formula C₅H₁₂O and give their IUPAC names.

(ii) Classify the isomers of alcohols in question 11.3 (i) as primary, secondary and tertiary alcohols.

Write structures of the compounds whose IUPAC names are as follows:

(i) 2-Methylbutan-2-ol

(ii) 1-Phenylpropan-2-ol

(iii) 3,5-Dimethylhexane -1, 3, 5-triol

(iv) 2,3 - Diethylphenol

(v) 1 - Ethoxypropane

(vi) 2-Ethoxy-3-methylpentane

(vii) Cyclohexylmethanol

(viii) 3-Cyclohexylpentan-3-ol

(ix) Cyclopent-3-en-1-ol

(x) 3-Chloromethylpentan-1-ol.

Write IUPAC names of the following compounds:

(i)

(ii)

(iii)

(iv)

(v)

(vi)

(vii)

(viii)

(ix)

(x) 

(xi) 

(xii)

Predict the products of the following reactions:

(i) 

(ii)

(iii)

(iv) 

Which of the following is an appropriate set of reactants for the preparation of 1-methoxy-4-nitrobenzene and why?

(i)

(ii)

Write the reactions of Williamson synthesis of 2-ethoxy-3-methylpentane starting from ethanol and 3-methylpentan-2-ol.

Write the equations involved in the following reactions:

(i) Reimer-Tiemann reaction

(ii) Kolbe's reaction

Ortho and para nitrophenols are more acidic than phenol. Draw the resonance structures of the corresponding phenoxide ions.

Predict the major product of acid catalysed dehydration of

(i) 1-Methylcyclohexanol and

(ii) Butan-1-ol

Give structures of the products you would expect when each of the following alcohol reacts with (a) HCl-ZnCl₂ (b) HBr and (c) SOCl₂.

(i) Butan-1-ol

(ii) 2-Methylbutan-2-ol

Write structures of the products of the following reactions:

(i)

(ii)

(iii)

Show how are the following alcohols prepared by the reaction of a suitable

Grignard reagent on methanal?

(i)

(ii)

Name the following compounds according to IUPAC system.

(i)

(ii)

(iii)

(iv)

(v)

Identify allylic alcohols in the above examples.

Classify the following as primary, secondary and tertiary alcohols:

(i)

(ii) 

(iii) 

(iv)

(v)

(vi)