Class 12 Chemistry Chapter 11 Alcohols, Phenols and Ethers MCQs | Class 12 Chemistry Chapter 11 Alcohols, Phenols and Ethers Objective Type Questions and Answers

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Questions
1 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:tertiary carbocation is more stable than primary carbocation
2 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:Tertiary alcohol by SN1
3 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: butan-2-ol
4 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:tertiary alcohol
5 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: tertiary alcohol
6 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:2, 4, 6-tribromophenol
7 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:2, 4, 6-trinitropheriol
8 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:o-nitrophenol shows intramolecular H-bonding
9 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: pyridiriium chlorochromate
10 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: (i) < (ii) < (iii)
11 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: electrophilic substitution reaction
12 he most suitable reagent for the conversion of RCH2OH → RCHO is
A K2Cr2O7
B CrO3
C KMnO4
D PCC

Answer: PCC
13 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: 1 -methylcyclohexene andbut-1-ene
14 Tertiary butyl alcohol gives tertiary butyl chlorideon treatment with
A Conc HCl/anhydrous ZnCl3
B KCN
C NaOCl
D Cl2

Answer:Conc HCl/anhydrous ZnCl3
15 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 p-CH3OC6H4CH(OH)CH3

Answer:p-CH3OC6H4CH(OH)CH3
16 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: Kolbe’s reaction and Reimer-Tiemann reaction
17 Which of the following is phenol?
A Cresol
B Catechol
C Benzenol
D All of these

Answer:All of these
18 Benzoquinone is prepared by reaction of phenol with
A Na2Cr2O7, H2SO4
B KMnO4, H2SO4
C Na2CrO4,HCl
D K2MnO4, H2SO4

Answer: Na2Cr2O7, H2SO4
19 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: salicylic acid
20 Which of the following compounds will give tribromo derivative on treatment with bromine water?
A 1.1
B 1.2
C 1.3
D 1.4

Answer: 1.2

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