Alcohol and Ether Previous Year Questions with Solutions are given here. Alcohol and ether are classes of organic compounds that find wide usage in industries as well as for domestic purposes. Alcohol is formed when a saturated carbon atom is bonded to a hydroxyl (-OH) group. Ether is formed when an oxygen atom is connected to two alkyl or aryl groups. BYJU’S provides solutions designed by our subject matter experts.
The main concepts include the classification of alcohol and ether, preparation and important reactions. Alcohol and Ether is an important topic included in the JEE syllabus for organic chemistry. Questions based on their reactions and methods of preparation are asked almost every year in JEE. This article helps students to find which type of questions are asked from the topic. Students can easily download the solutions in PDF format for free.
Download Alcohol and Ether Previous Year Solved Questions PDF
JEE Main Previous Year Solved Questions on Alcohol and Ether
1. Iodoform can be prepared from all except:-
(1) Isobutyl alcohol
(2) Ethyl methyl ketone
(3) Isopropyl alcohol
(4) 3-Methyl–2–butanone
Solution:
For the preparation of iodoform, the reactant should have -COCH3 group.
Isobutyl alcohol does not have -COCH3 group.
Hence option (1) is the answer.
2. In the Victor-Meyer’s test, the colour given by 10, 20 and 30 alcohols are respectively:-
(1) Red, blue, colourless
(2) Colourless, red, blue
(3) Red, blue, violet
(4) Red, colourless, blue
Solution:
In Victor Meyer’s test, the primary alcohol gives red colour, secondary alcohol gives blue colour and tertiary alcohol gives colourless.
Hence option (1) is the answer.
3. The most suitable reagent for the conversion of R – CH2 – OH → R – CHO is:
(1) CiO3
(2) PCC (Pyridinium chlorochromate)
(3) KMNO4
(4) K2Cr2O7
Solution:
R – CH2 – OH → R – CHO
PCC (Pyridinium chlorochromate) is the most suitable reagent for the above conversion, because it oxidises primary alcohol to aldehydes and secondary alcohols to ketones. It will not affect any other functional group. So it has high selectivity for the oxidation of alcohols.
Hence option (2) is the answer.
4. From Amongst the following alcohols the one that would react fastest with conc.HCl and anhydrous ZnCl2, is
(1) 2- Butanol
(2) 2- Methylpropan-2-ol
(3) 2-Methylpropanaol
(4) 1-Butanol
Solution:
2-Methylpropan-2-ol is tertiary alcohol. It reacts fast with conc. HCl and anhydrous ZnCl2
Hence option (2) is the answer.
5. An ether is more volatile than an alcohol having the same molecular formula. This is due to
(1) alcohols having resonance structures
(2) inter-molecular hydrogen bonding in ethers
(3) inter-molecular hydrogen bonding in alcohols
(4) dipolar character of ethers
Solution:
An ether is more volatile than an alcohol having the same molecular formula. This is due to intermolecular hydrogen bonding in alcohols.
Hence option (3) is the answer.
6. A liquid was mixed with ethanol and a drop of concentrated H2SO4 was added. A compound with a fruity smell was formed. The liquid was:-
(1) CH3COCH3
(2) CH3COOH
(3) CH3OH
(4) HCHO
Solution:
The fruity smell is the characteristic property of ester. So the reaction leads to the formation of ester. It is called esterification.
CH3COOH + C2H5OH → CH3COOC2H5 + H2O
Hence option (2) is the answer.
7. An unknown alcohol is treated with the “Lucas reagent’ to determine whether the alcohol is primary, secondary or tertiary. Which alcohol reacts fastest and by what mechanism:-
(1) secondary alcohol by SN1
(2) tertiary alcohol by SN1
(3) secondary alcohol by SN2
(4) tertiary alcohol by SN2
Solution:
Lucas test is done to differentiate between primary, secondary and tertiary alcohols. This is based on the difference in reactivity of the three classes of alcohols with hydrogen halides. The reaction proceeds through carbocation formation as tertiary carbocation is highly stable. Then the reaction proceeds through SN1 with tertiary alcohol.
Hence option (2) is the answer.
8. A and B are:
Solution:
Hence option (3) is the answer.
9. The product X will be
Solution:
1-Methyethylene oxide treated with excess HBr gives 2-4 dibromobutane.
Hence option (2) is the answer.
10. Phenyl magnesium bromide reacts with methanol to give
(1) a mixture of anisole and Mg(OH)Br
(2) a mixture of benzene and Mg(OMe)Br
(3) a mixture of toluene and Mg(OH)Br
(4) a mixture of phenol and Mg(Me)Br
Solution:
Phenyl magnesium bromide reacts with methanol to give a mixture of benzene and Mg(OMe)Br.
Hence option (2) is the answer.
11. The best reagent to convert pent-3- en-2-ol into pent-3-en-2-one is
(1) Acidic permanganate
(2) Acidic dichromate
(3) Chromic anhydride in glacial acetic acid
(4) Pyridinium chloro-chromate
Solution:
Chromic anhydride in glacial acetic acid is used for the conversion of secondary alcohol to ketone.
Hence option (3) is the answer.
12. In the following sequence of reactions, The compound D is
(1) Butanal
(2) n – butyl alcohol
(3) n – propyl alcohol
(4) propanol
Solution:
D is n – propyl alcohol
Hence option (3) is the answer.
13. Which of the following undergoes reaction with 50% sodium hydroxide solution to give the corresponding alcohol and acid?
(1) Phenol
(2) Benzoic acid
(3) Butanal
(4) Benzaldehyde
Solution:
Since Benzaldehyde does not contain a-hydrogen, it undergoes Cannizzaro’s reaction forming alcohol and acid.
Hence option (4) is the answer.
14. Acetyl bromide reacts with an excess of CH3MgI followed by treatment with a saturated solution of NH4Cl gives
(1) acetone
(2) acetyl iodide
(3) 2-methyl-2-propanol
(4) acetamide
Solution:
The reaction will give a tertiary alcohol.
Hence option (3) is the answer.
15. During dehydration of alcohols to alkenes by heating with conc. H2S04 the initiation step is
(1) formation of carbocation
(2) elimination of water
(3) formation of an ester
(4) protonation of the alcohol molecule
Solution:
Protonation of alcohol molecules is the initial step during the dehydration of alcohols to alkenes by heating with conc. H2So4.
Hence option (4) is the answer.
Also Read:
Alcohols Phenols and Ethers – Important Topics
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