Friday, 29 January 2021

CBSE Class 12 Chemistry - MCQ and Online Tests - Unit 11 - Alcohols, Phenols and Ethers

CBSE Class 12 Chemistry – MCQ and Online Tests – Unit 11 – Alcohols, Phenols and Ethers

Every year CBSE conducts board exams for 12th standard. These exams are very competitive to all the students. So our website provides online tests for all the 12th subjects. These tests are also very effective and useful for those who preparing for competitive exams like NEET, JEE, CA etc. It can boost their preparation level and confidence level by attempting these chapter wise online tests.

These online tests are based on latest CBSE Class 12 syllabus. While attempting these our students can identify the weak lessons and continuously practice those lessons for attaining high marks. It also helps to revise the NCERT textbooks thoroughly.


 

CBSE Class 12 Chemistry – MCQ and Online Tests – Unit 11 – Alcohols, Phenols and Ethers

Question 1.
Order of esterification of alcohols are
(a) 3° > 1° > 2°
(b) 2°> 3° > 1°
(c) 1 ° > 2° > 3°
(d) None of these

Answer

Answer: (c) 1 ° > 2° > 3°


Question 2.
What happens when tertiary butyl alcohol is passed over heated copper at 300°C?
(a) Secondary butyl alcohol is formed
(b) 2-methylpropene is formed
(c) 1-butene is formed
(d) Butanol is formed

Answer

Answer: (b) 2-methylpropene is formed


Question 3.
Which of the follow ing compounds will be most easily attacked by an electrophile?
MCQ Questions for Class 12 Chemistry Chapter 11 Alcohols, Phenols and Ethers with Answers 1

Answer

Answer: (c)


Question 4.
The decreasing order of boiling point of the following alcohols is
(a) 3-methylbuan-2-ol > 2-methylbutan-2-ol > pentan-1-ol
(b) Pentan-1-ol > 3-methylbutan-2-ol > 2-methylbutan-2-ol
(c) 2-methylbutan-2-ol > 3-methylbutan-2-ol > pentan-1-ol
(d) 2-methylbutan-2-ol > pental-1-ol > 3-methylbutan-2-ol

Answer

Answer: (b) Pentan-1-ol > 3-methylbutan-2-ol > 2-methylbutan-2-ol


Question 5.
MCQ Questions for Class 12 Chemistry Chapter 11 Alcohols, Phenols and Ethers with Answers 2
In the reaction, X is
(a) (CH3)2C = CHCH3
(b) CH3C = CH
(c) (CH3)2CHCH2CH3
MCQ Questions for Class 12 Chemistry Chapter 11 Alcohols, Phenols and Ethers with Answers 3

Answer

Answer: (a) (CH3)2C = CHCH3


Ans. a
Question 6.
What would be the reactant and reagent used to obtain 2, 4-dimenthyl pentan-3-ol?
(a) Propanal and propyl magnesium bromide
(b) 3-methylbutanal and 2-methyl magnesium iodide
(c) 2-dimethylpropanone and methyl magnesium odide
(d) 2-methylpropanal and isopropyl magnesium iodide

Answer

Answer: (d) 2-methylpropanal and isopropyl magnesium iodide


Question 7.
Vapours of an alcohol X when passed over hot reduced copper, produce an alkene, the alcohol is
(a) primary alcohol
(b) secondary alcohol
(c) tertiary alcohol
(d) dihydric alcohol

Answer

Answer: (c) tertiary alcohol


Question 8.
Acid catalysed dehydration of t-butanol is faster than that of n-butanol because
(a) tertiary carbocation is more stable than primary carbocation
(b) primary carbocation is more stable than tertiary carbocation
(c) t-butanol has a higher boiling point
(d) rearrangement takes place during dehydration of t- butanol

Answer

Answer: (a) tertiary carbocation is more stable than primary carbocation


Question 9.
An unknown alcohol is treated with “Lucas reagent” to determine whether the alcohol is primary, secondary or tertiary. Which alcohol reacts fastest and by what mechanism?
(a) Tertiary alcohol by SN2
(b) Secondary alcohol by SN1
(c) Tertiary alcohol by SN1
(d) Secondary alcohol by SN2

Answer

Answer: (c) Tertiary alcohol by SN1


Question 10.
Which of the following alcohols reacts most readily with Lucas reagent?
(a) CH3CH2CH2OH
MCQ Questions for Class 12 Chemistry Chapter 11 Alcohols, Phenols and Ethers with Answers 4

Answer

Answer: (c)


Question 11.
Picricacid is a yellow coloured compound. Its chemical name is
(a) m-nitrobenzoic acid
(b) 2, 4, 6-trinitropheriol
(c) 2, 4, 6-tribromophenol
(d) p-nitrophenol

Answer

Answer: (b) 2, 4, 6-trinitropheriol


Question 12.
One mole of ethyl acetate on tatment with an excess of LiAlH4 in dry ether and subsequent acidification produces
(a) 1 mole acetic acid + 1 mole ethyl alcohol
(b) 1 mole ethyl alcohol + 1 mole methyl alcohol
(c) 2 moles of ethyl alcohol
(d) 1 mole of 2-butanol

Answer

Answer: (c) 2 moles of ethyl alcohol


Question 13.
Which of the following alcohols gives 2-butenc on dehydration byconc. H2SO4?
(a) 2-methyl propene-2-ol
(b) 2-methyl 1 -propanol
(c) Butane-2-ol
(d) Butane 1-ol

Answer

Answer: (c) Butane-2-ol


Question 14.
Phenol when treated with excess of bromine water gives a white precipitate of
(a) 2, 4, 6-tribromophenol
(b) o-bromophenol
(c) p-bromophenol
(d) bromobenzene

Answer

Answer: (a) 2, 4, 6-tribromophenol


Question 15.
Ortho-nitrophenol is less soluble in water than, p- and m- nitrophenols because
(a) o-nitrophenol shows intramolecular H-bonding
(b) o-nitrophenol shows intermolecular H-bonding
(c) melting point of o-nitrophenol is lower than those of m- and p-isomers
(d) o-nitrophenol is more volatile in steam than those of m- and p-isomers

Answer

Answer: (a) o-nitrophenol shows intramolecular H-bonding


Question 16.
Which of the following alcohol is dehydrated most easily with cone. H2SO4?
(a) p-O2NC6H4CH(OH)CH3
(b) p-ClC6H4CH(OH)CH3
(c) p-CH3OC6H4CH(OH)CH3
(d) C6H5CH(OH)CH3

Answer

Answer: (c) p-CH3OC6H4CH(OH)CH3


Question 17.
The best reagent to convert pent-3-en-2-ol into pent-3-en- 2-one is
(a) acidic permanganate
(b) acidic dichromate
(c) chromic anhydride in glacial acetic acid
(d) pyridiriium chlorochromate

Answer

Answer: (d) pyridiriium chlorochromate


Question 18.
Identify the final product of the reaction sequence.
MCQ Questions for Class 12 Chemistry Chapter 11 Alcohols, Phenols and Ethers with Answers 5
(a) Benzophenone
(b) Acetophenone
(c) Diphenyl
(d) Methyl salicylate

Answer

Answer: (b) Acetophenone


Question 19.
Propanone on reaction with alkyl magnesium bromide followed by hydrolysis will produce
(a) primary alcohol
(b) secondary alcohol
(c) tertiary alcohol
(d) carboxylic acid

Answer

Answer: (c) tertiary alcohol


Question 20.
Arrange the following alcohols in order of increasing reactivity towards sodium metal.
(i) (CH3)3C-OH
(ii) (CH3)2CH-OH
(iii) CH3CH2OH
(a) (iii) < (ii) < (i)
(b) (ii) > (i) < (iii)
(c) (i) < (ii) < (iii)
(d) (iii) < (i) < (ii)

Answer

Answer: (c) (i) < (ii) < (iii)


Question 21.
An alcohol X when treated with hot cone. H2SO4 gave an alkene Y with formula C4H8. This alkene on ozonolysis gives single product with molecular formula C2H4O. The alcohol is
(a) butan-1-ol,
(b) butan-2-ol
(c) 2-methylpropan-1-ol
(d) 2,2-dimethylbutynal-1-oI

Answer

Answer: (b) butan-2-ol


Question 22.
The reaction between phenol and chloroform in the presence of aqueous NaOH is
(a) nucleophilic substitution reaction
(b) electrophilic addition reaction
(c) electrophilic substitution reaction
(d) nucleophilic addition reaction

Answer

Answer: (c) electrophilic substitution reaction


Question 23.
In the following reaction sequence Z is
MCQ Questions for Class 12 Chemistry Chapter 11 Alcohols, Phenols and Ethers with Answers 6
(a) butan-1-ol
(b) butan-2-ol
(c) 2-methylpropan-2-ol
(d) 1, 1-dimethylethanol

Answer

Answer: (c) 2-methylpropan-2-ol


Question 24.
The most suitable reagent for the conversion of RCH2OH → RCHO is
(a) K2Cr2O7
(b) CrO3
(c) KMnO4
(d) PCC

Answer

Answer: (d) PCC


Question 25.
Which of the following reagents can not, be used to oxidise primary alcohols to aldehydes?
(a) CrO3 in anhydrous medium
(b) KMnO4 in acidic medium
(c) Pyridinium chlorochromate
(d) Heat in the presence of Cu at 573 K

Answer

Answer: (b) KMnO4 in acidic medium


Question 26.
1-Phenylethanol can be prepared by the reaction of benzaldehyde with
(a) methyl bromide
(b) ethyl iodide and magnesium
(c) methyl iodide and magnesium (Grignard reagent’s)
(d) methyl bromide and aluminium bromide

Answer

Answer: (c) methyl iodide and magnesium (Grignard reagent’s)


Question 27.
Benzoquinone is prepared by reaction of phenol with
(a) Na2Cr2O7, H2SO4
(b) KMnO4, H2SO4
(c) Na2CrO4,HCl
(d) K2MnO4, H2SO4

Answer

Answer: (a) Na2Cr2O7, H2SO4


Question 28.
The major product obtained on interaction of phenol with sodium hydroxide and carbon dioxide is
(a) benzoic acid
(b) salicyaldehyde
(c) salicylic acid
(d) phthalic acid

Answer

Answer: (c) salicylic acid


Question 29.
Tertiary butyl alcohol gives tertiary butyl chlorideon treatment with
(a) Conc HCl/anhydrous ZnCl3
(b) KCN
(c) NaOCl
(d) Cl2

Answer

Answer: (a) Conc HCl/anhydrous ZnCl3


Question 30.
Conversion of phenol to salicyclic acid and to salicyaldehyde are known as (respectively)
(a) Reimer-Tiemann reaction and Kolbe’s reaction
(b) Williamson’s synthesis and Hydrobration-oxidation
(c) Kolbe’s reaction and Williamson’s synthesis
(d) Kolbe’s reaction and Reimer-Tiemann reaction

Answer

Answer: (d) Kolbe’s reaction and Reimer-Tiemann reaction


Question 31.
Which of the following alcohols will give the most stable carbocation during dehydration?
(a) 2-methyl-1-propanol
(b) 2-methyl-2-propanol
(c) 1-Butanol
(d) 2-Butanol

Answer

Answer: (b) 2-methyl-2-propanol


Question 32.
The major product of acid catalysed dehydration of 2-methylcyclohexanol and butan-1-ol are respectively
(a) 1 -methylcyclohexene andbut-1-ene
(b) 2-methylcyclohexene and but-2-ene
(c) 2-methylcyclohexene and butane
(d) 1-methylcyclohexene and but-2-ene

Answer

Answer: (a) 1 -methylcyclohexene andbut-1-ene


Question 33.
Which of the following is phenol?
(a) Cresol
(b) Catechol
(c)Benzenol
(d) All of these

Answer

Answer: (d) All of these


Question 34.
Which of the following compounds will give tribromo derivative on treatment with bromine water?
MCQ Questions for Class 12 Chemistry Chapter 11 Alcohols, Phenols and Ethers with Answers 7

Answer

Answer: (b)


Question 35.
A compound X with the molecular formula C2H8O can be oxidised to another compound Y whose molecular formulae is C3H6O2. The compound X may be
(a) CH3CH2OCH3
(b) CH3CH2CHO
(c) CH3CH2CH2OH
(d) CH3CHOHCH3

Answer

Answer: (c) CH3CH2CH2OH


 

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