Bihar Board 12th Chemistry Objective Answers Chapter 11 Alcohols, Phenols and Ethers

Bihar Board 12th Chemistry Objective Questions and Answers

Bihar Board 12th Chemistry Objective Answers Chapter 11 Alcohols, Phenols and Ethers

Question 1.
IUPAC name of

(a) 3-propylbutan-l-ol
(b) 2-ethylpentan-l-ol
(c) 3-methyl hydroxyhexane
(d) 2-ethyl-2-propyl ethanol
Answer:
(a) 3-propylbutan-l-ol

Question 2.
A compound C₆H₄O₂ has two tertiary alcoholic groups. The IUPAC name of this compound is
(a) 2, 3-dimethyl-l, 2-butanediol
(b) 3, 3-dimethyl-l, 2-butanediol
(c) 2, 3-dimethyl-2, 3-butanediol
(d) 2-methyl-2, 3-pentanediol
Answer:
(c) 2, 3-dimethyl-2, 3-butanediol

Question 3.
Which of the following is phenol ?
(a) Cresol
(b) Catechol
(c) Benzenol
(d) All of these
Answer:
(d) All of these

Question 4.
The C—O—C angle in ether is about
(a) 180°
(b) 190°28′
(c) 110°
(d) 105°
Answer:
(c) 110°

Question 5.
The best method to prepare 3-methylbutan-2-ol from 3- methylbut-l-ene is
(a) addition of water in presence of dil. H₂SO₄
(b) addition of HCl followed by reaction with dil. NaOH
(c) hydroboration-oxidation reaction
(d) Reimer-Tiemann reaction
Answer:
(a) addition of water in presence of dil. H₂SO₄

Question 6.
An alkene CH₃CH = CH₂ is treated with B₂H₆ in presence of H₂0₂. The final product formed is
(a) CH₃CH₂CHO
(b) CH₃CH(OH)CH₃
(c) CH₃CH₂CH₂OH
(d) (CH₃CH₂CH₂)₃B
Answer:
(c) CH₃CH₂CH₂OH

Question 7.
Which reducing agent is used for the following conversion ?
RCOOH → RCH ₂OH
(a) LiAlH₄
(b) NaBH₄
(c) K₂Cr₂O₇
(d) KMnO₄
Answer:
(a) LiAlH₄

Question 8.
Tertiary butyl alcohol can be prepared by the reaction of
(a) acetaldehyde and ethyl magnesium iodide
(b) acetone and methyl magnesium iodide
(c) formaldehyde and propyl magnesium iodide
(d) butanone and methyl magnesium iodide
Answer:
(b) acetone and methyl magnesium iodide

Question 9.
1-Phenylethanol can be prepared by the reaction of benzaldehyde with
(a) methyl bromide
(b) ethyl iodide and magnesium
(c) methyl iodide and magnesium
(d) methyl bromide and aluminium bromide
Answer:
(c) methyl iodide and magnesium

Question 10.
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:
(c) tertiary alcohol

Question 11.
In the following sequence of reactions,

the compound Q formed will be
(a) aniline
(b) phenol
(c) benzaldehyde
(d) benzene sulphonic acid
Answer:
(b) phenol

Question 12.
Cumene on reaction with oxygen followed by hydrolysis gives
(a) CH₃OH and C₆H₅COCH₃
(b) C₆H₅OH and (CH₃)₂O
(c) C₆H₅OCH₃ and CH₃OH
(d) C₆H₅OH and CH₃COCH₃
Answer:
(d) C₆H₅OH and CH₃COCH₃

Question 13.
The decreasing order of boiling points of the following alcohols is
(a) 3-methylbutan-2-ol > 2-methylbutan-2-ol > pentain- l-ol            .
(b) pentan-l-ol > 3-methylbutan-2-ol > 2-methylbutan- 2-ol
(c) 2-methyIbutan-2-ol > 3-methylbutan-2-ol > pentan- l-ol
(d) 2-methylbutan-2-ol > pentan-l-ol > 3-methylbutan- 2-ol
Answer:
(b) pentan-l-ol > 3-methylbutan-2-ol > 2-methylbutan- 2-ol

Question 14.
Arrange the following compounds in increasing order of boiling points. Propan-l-ol, butan-l-ol, butan-2-ol,
pentan-1-ol.
(a) Propan-1-ol, butan-2-ol, butan-1-ol, pentan-1-ol
(b) Propan-1-ol, butan-1-ol, butan-2-ol, pentan-1-ol
(c) Pentan-1-ol, butan-2-ol, butan-1-ol, propan-1-ol
(d) Pentan-1-ol, butan-1,-ol, butan-2,-ol, propan-1-ol
Answer:
(a) Propan-1-ol, butan-2-ol, butan-1-ol, pentan-1-ol

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:

Question 16.
For the reaction C₂H₅OH + HX → C₂H₅X + H₂O ; the order of reactivity is
(a) HCl>HBr>HI
(b) HI>HBr>HCl
(c) HBr > HCl > HI
(d) HI > HCl > HBr
Answer:
(b) HI>HBr>HCl

Question 17.
Which of the following is the prople method to prepare n-hexane from n-propyl alcohol ?

(a) (X) → HBr,(Y) → HCN
(b) (X) →HBr,(Y) → Na,ether
(c) (X) → Br₂,(Y)→ CH₃CN
(d) (X) →  Br₂,(Y) → KMnO₄
Answer:
(b) (X) →HBr,(Y) → Na,ether

Question 18.
Which of the following compounds does not react with NaOH?
(a) CH₃COOH
(b) CH₃CONH₂
(c) C₆H₅OH
(d) CH₃CH₂OH
Answer:
(d) CH₃CH₂OH

Question 19.
Out of 2-chloroethanol and ethanol which is more acidic and why ?
(a) 2-Chloroethanol due to +1 effect of Cl
(b) Ethanol due to +1 effect of CH₃
(c) 2-Chloroethanol due to -1 effect of Cl
(d) Ethanol due to -1 effect of CH₃
Answer:
(c) 2-Chloroethanol due to -1 effect of Cl

Question 20.
The correct sequence of decreasing acidity is
(a) (CH₃)₃COH > (CH₃)₂CHOH > C₂H₅OH > CH₃OH
(b) CH₃OH > C₂H₅OH > (CH₃)₂CHOH > (CH₃)₃COH
(c) C₂H₅OH > CH₃OH > (CH₃)₃COH > (CH₃)₂CHOH
(d) (CH₃)₂CHOH > (CH₃)₃COH > C₂H₅OH >CH₃OH
Answer:
(b) CH₃OH > C₂H₅OH > (CH₃)₂CHOH > (CH₃)₃COH

Question 21.
Order of esterification of alcohols is
(a) 3°> 1°> 2°
(b) 2°>3°> 1°
(c) r>2°>3°
(d) none of these
Answer:
(c) r>2°>3°

Question 22.
Which of the following alcohols reacts most readily with Lucas reagent ?

Answer:
(c)

Question 23.
Tertiary butyl alcohol gives tertiary butyl chloride on treatment with
(a) HCl/anhydrous ZnCl₂
(b) KCN
(c) NaOCl
(d) Cl₂
Answer:
(a) HCl/anhydrous ZnCl₂

Question 24.
R-OH + HX → RX + H₂O
In the above reaction, the reactivity of alcohols is
(a) tertiary > secondary > primary
(b) tertiary < secondary < primary
(c) tertiary > primary > secondary
(d) secondary > primary > tertiary
Answer:
(a) tertiary > secondary > primary

Question 25.
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:
(b) 2-Methyl-2-propanol

Question 26.
 in the reaction X is,
(a) (CH₃)₂ C = CHCH₃
(b) CH₃C = CH
(c) (CH₃)₂CHCH₂CH₃

Answer:
(a) (CH₃)₂ C = CHCH₃

Question 27.
The major product of acid catalysed dehydration of 2- meyhylcyclohexanol and butan-l-ol are respectively
(a) 1-methylcyclohexene and but-l-ene
(b) 2-methylcyclohexene and but-2-ene
(c) 2-methylcyclohexene and butane
(d) 1-methylcyohexene and but-2-ene
Answer:
(a) 1-methylcyclohexene and but-l-ene

Question 28.
A compound X with the molecular formula C₃H₈O can be oxidised to another compound Y whose molecular formula is C₃H₆O₂. The compound X may be
(a) CH₃CH₂OCH₃
(b) CH₃CH₂CHO
(c) CH₃CH₂CH₂OH
(d) CH₃CHOCH₃
Answer:
(c) CH₃CH₂CH₂OH

Question 29.
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) pyridinium chlorochromate
Answer:
(d) pyridinium chlorochromate

Question 30.
The most suitable reagnent for the conversion of RCH₂OH → RCHO is
(a) K₂Cr₂O₇
(b) CrO₃
(c) KMnO₄
(d) PCC
Answer:
(d) PCC

Question 31.
Conversion of ethyl alcohol into acetaldehyde is an example of
(a) hydrolysis
(b) oxidation
(c) reduction
(d) molecular rearrangement
Answer:
(b) oxidation

Question 32.
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:
(c) tertiary alcohol

Question 33.
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) Butanal is formed
Answer:
(b) 2-Methylpropene is formed

Question 34.
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:
(b) KMnO₄ in acidic medium

Question 35.
Which of the following compounds will be most easily attacked by an electrophile ?

Answer:
(c)

Question 36.
Picric acid is a yellow coloured compound. Its chemical name is
(a) m-nitrobenzoic acid
(b) 2, 4, 6-trinitrophenol
(c) 2, 4, 6-tribromophenol
(d) p-nitrophenol
Answer:
(b) 2, 4, 6-trinitrophenol

Question 37.
Phenol when treated with excess of bromine water gives a white precipite of
(a) 2, 4, 6-tribromophenol
(b) o-bromophenol
(c) p-bromophenol
(d) bromobenzene
Answer:
(a) 2, 4, 6-tribromophenol

Question 38.
The major product obtained on interaction of phenol with sodium hydroxide and carbon dioxide is
(a) benzoic acid
(b) salicylaldehyde
(c) salicylic acid
(d) phthalic acid
Answer:
(c) salicylic acid

Question 39.
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:
(c) electrophilic substitution reaction

Question 40.
Benzoquinone is prepared by reaction of phenol with
(a) Na₂Cr₂O₇,H₂SO₄
(b) KMnO₄,H₂SO₄
(c) NaCrO₄,HCl
(d) K₂MnO₄,H₂SO₄
Answer:
(a) Na₂Cr₂O₇,H₂SO₄

Question 41.
Consider the following reaction,

The product Z is
(a) benzaldehyde
(b) benzoic acid
(c) benzene
(d) toluene
Answer:
(b) benzoic acid

Question 42.
Methyl alcohol is industrially prepared by the action of
(a) CH₃COCH₃
(b) CO + H₂
(c) CH₃COOH
(d) C₂H₅OH
Answer:
(b) CO + H₂

Question 43.
The enzyme which can catalyse the conversion of glucose to ethanol is
(a) inverstase
(b) zymase
(c) maltase
(d) diastase
Answer:
(b) zymase

Question 44.
An equimolar quantities of ethanol and propanol is heated with cone. H₂SO₄. The product formed is/are
(a) C₂H₅OC₂H₅
(b) C₃H₇OC₃H₇
(c) C₂H₅OC₃H₇
(d) all of these
Answer:
(d) all of these

Question 45.
Which of the following alcohols gives the best yield of dialkyl ether on being heated with a trace of sulphuric acid ?
(a) 2-Pentanol
(b) 2-Methyl-2-butanol
(c) 1-Pentanol
(d) 2-Propanol
Answer:
(c) 1-Pentanol

Question 46.
Ether is obtained from ethyl alcohol in presence of.H₂SO₄ at
(a) 113 K
(b) 443 K
(c) 413K
(d) 213 K
Answer:
(c) 413K

Question 47.
Correct order of boiling points among following is

(a) X > Y > Z
(b) Y > X > Z
(c) Z > X > Y
(d) Z > Y > X
Answer:
(c)

Question 48.
Which of the following are the products shown by the reaction of methoxyethane with HI ?
(a) C₂H₅I + CH₃OH
(b) CH₃I + H₂O
(c) C₂H₅OH + H₂O
(d) C₂H₅OH+CH₃I
Answer:
(d) C₂H₅OH+CH₃I

Question 49.
Which of the following products are not correctly matched in the given reaction ?

Answer
(b)

Question 50.
The ether that undergoes electrophilic substitution reaction is
(a) CH₃OC₂H₅
(b) C₆H₅OCH₃
(c) CH₃OCH₃
(d) C₂H₅OC₂H₅
Answer:
(b) C₆H₅OCH₃

Question 51.
Anisole on reaction with chloromethane in presence of anhydrous AlCl₃ gives
(a) o-methyl aniosle and p-methoxy anisole
(b) p-methyl anisole and p-methoxy aniosle
(c) o-methyl anisole and p-methyl anisole
(d) o-methoxy acetophenone and p-methoxy acetophenone
Answer:
(c) o-methyl anisole and p-methyl anisole

Question 52.
Monochlorination of toluene in sunlight followed by hydrolysis with aq. NaOH yields
(a) o-cresol
(b) m-cresol
(c) 2,4-dihydroxytoluene
(d) benzyl alcohol
Answer:
(d) benzyl alcohol

Question 53.
How many alcohols with molecular formula C₄H₁₀O are chiral in nature ?
(a) 1
(b) 2
(c) 3
(d) 4
Answer:
(a) 1

Question 54.
CH₃CH₂OH can be converted into CH₃CHO by
(a) catalytic hydrogenation
(b) treatment with Li AlH₄
(c) treatment with pyridinium chlorochromate
(d) treatment with KMnO₄
Answer:
(c) treatment with pyridinium chlorochromate

Question 55.
The process of converting halides into alcohols involves
(a) addition reaction
(b) substitution reaction
(c) dehydrohalogenation reaction
(d) rearrangement reaction
Answer:
(b) substitution reaction

Question 56.
Give IUPAC name of the compound given below :

(a) 2-Chloro-5-hydroxyhexane
(b) 2-Hydroxy-5-chlorohexane
(c) 5-Chlorobexan-2-ol
(d) 2-Chlorohexan-5-ol
Answer:
(c) 5-Chlorobexan-2-ol

Question 57.
IUPAC name of m-cresol is
(a) 3-methylphenol
(b) 3-chlorophenol
(c) 3-methoxyphenol
(d) benzene-1,3-diol
Answer:
(a) 3-methylphenol

Question 58.
IUPAC name of the compound

(a) 1-methoxy-1-methylethane
(b) 2-methoxy-2-methyIethane
(c) 2-methoxypropane
(d) isopropyl methyl ether
Answer:
(c) 2-methoxypropane

Question 59.
Which of the following species can act as the strongest base ?
(a) – OH
(b) – OR
(c) – OC₆H₅
(d)

Answer:
(b) – OR

Question 60.
Which of the following compounds will react with sodium hydroxide solution in water ?
(a) C₆H₅OH
(b) C₆H₅CH₂OH
(c) (CH₃)₃COH
(d) C₂H₅OH
Answer:
(a) C₆H₅OH

Question 61.
Phenol is less acidic than
(a) ethanol
(b) o-nitrophenol
(c) o-methylphenol
(d) o-methoxphenol
Answer:
(b) o-nitrophenol

Question 62.
Which of the following is most acidic ?
(a) Benzyl alcohol
(b) Cyclohexanol
(c) Phenol
(d) m-Chlorophenol
Answer:
(d) m-Chlorophenol