Alcohols Phenols and Ethers — CBSE Class 12 board PYQs

Out of the following alkenes, the one which will produce tertiary butyl alcohol on acid-catalysed hydration is:

Assertion (A): p-Methoxyphenol is a stronger acid than p-nitrophenol.
Reason (R): The methoxy group shows a +I effect whereas the nitro group shows a −I effect.

Which of the following alcohols will not undergo oxidation?

The iodoform test is not given by:

The substitution reaction of an alkyl halide mainly occurs by the SN1 or SN2 mechanism. Whatever mechanism alkyl halides follow for the substitution reaction to occur, the polarity of the carbon-halogen bond is responsible for these substitution reactions. The rate of SN1 reactio …

Write the IUPAC name of the compound shown in the figure (CH${}_3$CH(OH)–C(CH${}_3$)${}_2$–CH${}_2$CH${}_3$).

Write the IUPAC name of the compound shown in the figure (a dinitrophenol).

How would you convert ethanol to ethene?

Write the structure of the molecule of the compound whose IUPAC name is 1-phenylpropan-2-ol.

Give the IUPAC name of the compound shown in the figure (CH${}_2$=CH–CH(OH)–CH${}_2$CH${}_2$CH${}_3$).

Give the IUPAC name of the compound shown in the figure ((CH${}_3$)${}_2$C=C(Br)–CH${}_2$OH).

Write the IUPAC name of the compound shown in the figure (CH${}_3$OCH${}_2$CH(CH${}_3$)CH${}_2$CH${}_3$).

Write the IUPAC name of the compound shown in the figure (the same dimethyl hexanediol skeleton).

How is ethanol obtained from 2-butene?

Give a reason for the following: o-nitrophenol is more acidic than o-methoxyphenol.

How is tertiary butyl alcohol obtained from acetone?

Write the IUPAC name of the compound shown in the figure (C${}_6$H${}_5$CH${}_2$OH).

How is phenol obtained from aniline?

How is acetone obtained from 2-bromopropane?

Write the IUPAC name of the compound shown in the figure (a dimethylphenol).

How will you distinguish between 1-propanol and 2-propanol by a suitable chemical test?

Give a chemical test to distinguish between phenol and benzoic acid.

Account for the following: o-nitrophenol has a lower boiling point than p-nitrophenol.

How is CO converted into methanol?

In the absence of kerosene oil, can we store sodium in diethyl ether, ethyl alcohol or anhydrous hexanol?

Explain why phenol is an acid but ethanol is neutral.

Give the structural formula and name of the product of the following reaction: phenol is treated with excess of aqueous bromine.

Mention two important uses of methanol.

Mention an industrial product manufactured from methanal.

Of the two hydroxyl organic compounds ROH and R'OH, the first is basic and the other is acidic in behaviour. How is R different from R'?

Write the IUPAC name of aspirin.

Write the IUPAC name of the following compound: (CH${}_3$)${}_3$COH

Write the IUPAC name of the compound shown in the figure (CH${}_3$OCH${}_2$CH(OH)CH${}_3$).

Write the IUPAC name of the compound shown in the figure (a dimethyl hexanediol).

Give the structure of the major product expected from each of the following reactions:
(a) reaction of ethanal with methyl magnesium bromide followed by hydrolysis
(b) hydration of but-1-ene in the presence of dilute sulphuric acid
(c) reaction of phenol with bromine water

Write the structures of compounds A and B in each of the two reaction sequences shown in the figure.

(a) Arrange the following compounds in increasing order of their acid strength: p-cresol, p-nitrophenol, phenol.
(b) Write the mechanism (using curved-arrow notation) of the following reaction:

Write the chemical equations involved in the following reactions:
i) Kolbe's reaction
ii) Friedel–Crafts acetylation of anisole
OR
How do you convert:
i) phenol to toluene
ii) formaldehyde to ethanol

Write the mechanism of the following reaction:

Give reasons for the following:
(a) Protonation of phenols is difficult whereas ethanol easily undergoes protonation.
(b) The boiling point of ethanol is higher than that of dimethyl ether.
(c) Anisole on reaction with HI gives phenol and CH${}_3$I as main products and not iodobenz …

Predict the products of the following reactions:
i) (the oxidation shown in the figure)
ii) C${}_6$H${}_5$–CO–CH${}_3$ →(NaOH/I${}_2$)→ ? + ?
iii) CH${}_3$COONa →(NaOH/CaO, Δ)→ ?

a) Write the mechanism of the following reaction:

b) Write the equation involved in the acetylation of salicylic acid.

How would you obtain:
i) picric acid (2,4,6-trinitrophenol) from phenol
ii) 2-methylpropene from 2-methylpropanol

How would you obtain the following?
i) benzoquinone from phenol
ii) 2-methylpropan-2-ol from methyl magnesium bromide
iii) propan-2-ol from propene

Illustrate the following reactions, giving a chemical equation for each:
i) Kolbe's reaction
ii) Friedel–Crafts acetylation of anisole

How would you convert the following?
i) phenol to benzoquinone
ii) propanone to 2-methylpropan-2-ol
iii) propene to propan-2-ol

Complete the two reactions shown in the figure (Delhi 2009 pair — an ether cleavage and a ring substitution).

Explain the following observations:
i) The boiling point of ethanol is higher than that of methoxymethane.
ii) Phenol is more acidic than ethanol.
iii) o- and p-nitrophenols are more acidic than phenol.

Write one chemical reaction each to illustrate the following:
i) Reimer–Tiemann reaction
ii) Williamson's synthesis

Describe the mechanism of alcohols reacting both as nucleophiles and as electrophiles in their reactions.

Name the reagents used in the following conversions:
i) a primary alcohol to an aldehyde
ii) butan-2-one to butan-2-ol
iii) phenol to 2,4,6-tribromophenol

a) Name the reagents and write the chemical equation for the preparation of ethoxybenzene by Williamson's synthesis.
b) Why do phenols not undergo protonation reactions readily?

How may the following conversions be carried out?
i) propene to propan-2-ol
ii) anisole to phenol (write the reaction only)

How would you account for the following?
i) Phenols are much more acidic than alcohols.
ii) The boiling points of ethers are much lower than those of alcohols of comparable molar masses.

How are the following conversions carried out?
i) propene to propan-2-ol
ii) phenol to salicylaldehyde

How are the following conversions carried out?
a) benzyl chloride to benzyl alcohol
b) ethyl magnesium bromide to propan-1-ol

Write the reactions and the conditions involved in the conversion of:
a) propene to 1-propanol
b) phenol to salicylic acid

How are the following conversions carried out (write the reactions and conditions in each case)?
i) ethanol to 2-propanol
ii) phenol to acetophenone

Explain how an –OH group attached to a carbon in the benzene ring activates benzene towards electrophilic substitution.

How are the following conversions carried out (write reactions with conditions)?
a) 1-propanol to 1-chloro-2-propanol
b) phenol to salicylic acid

Describe why the hydroxyl group attached to an aromatic ring is more acidic than the hydroxyl group attached to an alkyl group. How does the presence of a nitro group in phenol affect its acidic character?

What happens when ethanol is heated with concentrated sulphuric acid at 453 K? Explain the mechanism of this reaction.

Complete the two reactions shown in the figure.

Write reactions and conditions for the following conversions:
i) 2-propanone into 2-methyl-2-propanol
ii) n-propyl alcohol into hexane

Of ethanol and n-propanol, which one gives the iodoform test, and why?

Write the IUPAC names of the three compounds shown in the figure.

Write the IUPAC names of the two compounds shown in the figure.

Explain, giving reasons, why:
i) phenol has a smaller dipole moment than methanol;
ii) phenol undergoes electrophilic substitution reactions.

a) Give a chemical test to distinguish between phenol and ethanol under seemingly similar conditions.
b) Write the reaction equation for what happens when tertiary butyl alcohol is heated over reduced copper at about 573 K.

a) Give reasons for the following: phenol does not undergo protonation readily.
b) Give a chemical test to distinguish between the following pair of compounds: 2-butanol and 2-methyl-2-propanol.

Why is it that phenol is acidic and hexanol is neutral towards a solution of NaOH?

Write the structures of the products when butan-2-ol reacts with the following:
(a) CrO${}_3$
(b) SOCl${}_2$

Write the main product(s) of each of the following reactions:
a) (the reaction shown in the figure)
b) CH${}_3$–CH=CH${}_2$ →(i) B${}_2$H${}_6$ (ii) H${}_2$O${}_2$/OH⁻→
c) C${}_6$H${}_5$–OH →(i) aq. NaOH (ii) CO${}_2$, H⁺→

(a) Out of t-butyl alcohol and n-butanol, which one undergoes acid-catalysed dehydration faster, and why? (2)
(b) Carry out the following conversions: (1×3)
(i) phenol to salicylaldehyde
(ii) t-butyl chloride to t-butyl ethyl ether
(iii) propene to propanol

(a) Give the mechanism for the formation of ethanol from ethene. (2)
(b) Predict the reagent for carrying out the following conversions: (1×3)
(i) phenol to benzoquinone
(ii) anisole to p-bromoanisole
(iii) phenol to 2,4,6-tribromophenol

(a) How do you convert the following?
(i) phenol to anisole
(ii) ethanol to propan-2-ol
(b) Write the mechanism of the following reaction:

(c) Why does phenol undergo electrophilic substitution more easily than be …

(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-butyl methyl ether.
(b) Write the reactions involved in:
(i) the Reimer–Tiemann reaction
(ii) Frie …