Q1Multiple choice
Monochlorination of toluene in sunlight followed by hydrolysis with aq. NaOH yields.
- (i)o-Cresol
- (ii)m-Cresol
- (iii)2, 4-Dihydroxytoluene
- (iv)Benzyl alcohol
Show answer
(iv) Benzyl alcohol
Chapter 11
Class 12 Chemistry · 74 questions · 73 with answers
Questions
Q2Multiple choice
How many alcohols with molecular formula C4H10O are chiral in nature?
- (i)1
- (ii)2
- (iii)3
- (iv)4
Show answer
(i) 1
Q3Multiple choice
What is the correct order of reactivity of alcohols in the following reaction? ZnCl R—OH + HCl → R—Cl + H2O
- (i)1° > 2° > 3°
- (ii)1° < 2° > 3°
- (iii)3° > 2° > 1°
- (iv)3° > 1° > 2°
Show answer
(iii) 3° > 2° > 1°
Q4Multiple choice
CH3CH2OH can be converted into CH3CHO by ______________.
- (i)catalytic hydrogenation
- (ii)treatment with LiAlH4
- (iii)treatment with pyridinium chlorochromate
- (iv)treatment with KMnO4
Show answer
(iii) treatment with pyridinium chlorochromate
Q5Multiple choice
The process of converting alkyl halides into alcohols involves_____________.
- (i)addition reaction
- (ii)substitution reaction
- (iii)dehydrohalogenation reaction
- (iv)rearrangement reaction
Show answer
(ii) substitution reaction
Q6Multiple choice
Which of the following compounds is aromatic alcohol?
- (i)A, B, C, D
- (ii)A, D
- (iii)B, C
- (iv)A
Show answer
(iii) B, C
Q7Multiple choice
Give IUPAC name of the compound given below.
- (i)2-Chloro-5-hydroxyhexane
- (ii)2-Hydroxy-5-chlorohexane
- (iii)5-Chlorohexan-2-ol
- (iv)2-Chlorohexan-5-ol
Show answer
(iii) 5-Chlorohexan-2-ol
Q8Multiple choice
IUPAC name of m-cresol is ___________.
- (i)3-methylphenol
- (ii)3-chlorophenol
- (iii)3-methoxyphenol
- (iv)benzene-1,3-diol
Show answer
(i) 3-methylphenol
Q9Multiple choice
IUPAC name of the compound is ______________.
- (i)1-methoxy-1-methylethane
- (ii)2-methoxy-2-methylethane 155 Alcohols, Phenols and Ethers
- (iii)2-methoxypropane
- (iv)isopropylmethyl ether
Show answer
(iii) 2-methoxypropane
Q10Multiple choice
Which of the following species can act as the strongest base?
- (i)OH
- (ii)OR
- (iii)O C6H5
- (iv)
Show answer
(ii) OR
Q11Multiple choice
Which of the following compounds will react with sodium hydroxide solution in water?
- (i)C6H5OH
- (ii)C6H5CH2OH
- (iii)(CH3)3 COH
- (iv)C2H5OH
Show answer
(i) C6H5OH
Q12Multiple choice
Phenol is less acidic than ______________.
- (i)ethanol
- (ii)o-nitrophenol
- (iii)o-methylphenol
- (iv)o-methoxyphenol
Show answer
(ii) o-nitrophenol
Q13Multiple choice
Which of the following is most acidic?
- (i)Benzyl alcohol
- (ii)Cyclohexanol
- (iii)Phenol
- (iv)m-Chlorophenol
Show answer
(iv) m-Chlorophenol
Q14Multiple choice
Mark the correct order of decreasing acid strength of the following compounds.
- (i)e>d>b>a>c
- (ii)b>d>a>c>e
- (iii)d>e>c>b>a
- (iv)e>d>c>b>a
Show answer
(ii) b>d>a>c>e
Q15Multiple choice
Mark the correct increasing order of reactivity of the following compounds with HBr/HCl.
- (i)a<b<c
- (ii)b<a<c
- (iii)b<c<a
- (iv)c<b<a
Show answer
(iii) b<c<a
Q16Multiple choice
Arrange the following compounds in increasing order of boiling point. Propan-1-ol, butan-1-ol, butan-2-ol, pentan-1-ol
- (i)Propan-1-ol, butan-2-ol, butan-1-ol, pentan-1-ol
- (ii)Propan-1-ol, butan-1-ol, butan-2-ol, pentan-1-ol
- (iii)Pentan-1-ol, butan-2-ol, butan-1-ol, propan-1-ol
- (iv)Pentan-1-ol, butan-1-ol, butan-2-ol, propan-1-ol
Show answer
(i) Propan-1-ol, butan-2-ol, butan-1-ol, pentan-1-ol
Q17Multiple correct
Which of the following are used to convert RCHO into RCH2OH?
- (i)H2/Pd
- (ii)LiAlH4
- (iii)NaBH4
- (iv)Reaction with RMgX followed by hydrolysis
Show answer
(i) H2/Pd
(ii) LiAlH4
(iii) NaBH4
Q18Multiple correct
Which of the following reactions will yield phenol?
- (i)157 Alcohols, Phenols and Ethers
- (ii)
- (iii)
- (iv)
Show answer
(i) 157 Alcohols, Phenols and Ethers
(ii)
(iii)
Q19Multiple correct
Which of the following reagents can be used to oxidise primary alcohols to aldehydes?
- (i)CrO3 in anhydrous medium.
- (ii)KMnO4 in acidic medium.
- (iii)Pyridinium chlorochromate.
- (iv)Heat in the presence of Cu at 573K.
Show answer
(i) CrO3 in anhydrous medium.
(iii) Pyridinium chlorochromate.
(iv) Heat in the presence of Cu at 573K.
Q20Multiple correct
Phenol can be distinguished from ethanol by the reactions with _________.
- (i)Br2/water
- (ii)Na
- (iii)Neutral FeCl3
- (iv)All the above
Show answer
(i) Br2/water
(iii) Neutral FeCl3
Q21Multiple correct
Which of the following are benzylic alcohols?
- (i)C6H5—CH2—CH2OH
- (ii)C6H5—CH2OH
- (iii)
- (iv)
Show answer
(ii) C6H5—CH2OH
(iii)
Q22Short answer
What is the structure and IUPAC name of glycerol?
Show answer
; Propane-1,2,3-triol
Q23Multiple choice
Write the IUPAC name of the following compounds.
- (A)
- (B)
Show answer
(A)
(B)
Q24Short answer
Write the IUPAC name of the compound given below.
Show answer
3-Methylpent-2-ene-1,2-diol
Q25Short answer
Name the factors responsible for the solubility of alcohols in water.
Show answer
(i) Hydrogen bonding (ii) Size of alkyl/aryl group.
Q26Short answer
What is denatured alcohol?
Show answer
Alcohol is made unfit for drinking by mixing some copper sulphate and pyridine in it. This is called denatured alcohol.
Q27Short answer
Suggest a reagent for the following conversion.
Show answer
CrO3 , pyridine and HCl. (Pyridinium chlorochromate)
Q28Short answer
Out of 2-chloroethanol and ethanol which is more acidic and why?
Show answer
2-Chloroethanol, due to –I effect of chlorine atom.
Q29Short answer
Suggest a reagent for conversion of ethanol to ethanal.
Show answer
CrO3, Pyridine and HCl (Pyridinium chlorochromate)
Q30Short answer
Suggest a reagent for conversion of ethanol to ethanoic acid.
Show answer
Any strong oxidising agent e.g., acidified KMnO4 or K2Cr2O7 .
Q31Short answer
Out of o-nitrophenol and p-nitrophenol, which is more volatile? Explain.
Show answer
Ortho nitrophenol, [Hint : intramolecular hydrogen bonding in o-nitrophenol and intermolecular hydrogen bonding in p-nitrophenol.]
Q32Short answer
Out of o-nitrophenol and o-cresol which is more acidic?
Show answer
o-Nitrophenol, [Hint : CH3 group is electron releasing]
Q33Short answer
When phenol is treated with bromine water, white precipitate is obtained. Give the structure and the name of the compound formed.
Show answer
(2, 4, 6- Tribromophenol)
Q34Short answer
Arrange the following compounds in increasing order of acidity and give a suitable explanation. Phenol, o-nitrophenol, o-cresol
Show answer
Increasing order of acidity : o-cresol < phenol < o-nitrophenol 165 Alcohols, Phenols and Ethers [Hint : In substituted phenols, the presence of electron withdrawing groups, enhance the acidic strength of phenol whereas, electron releasing groups decrease the acidic strength of phenol.]
Q35Short answer
Alcohols react with active metals e.g. Na, K etc. to give corresponding alkoxides. Write down the decreasing order of reactivity of sodium metal towards primary, secondary and tertiary alcohols.
Show answer
Decreasing order of reactivity of sodium metal is : 1° > 2° > 3°
Q36Short answer
What happens when benzene diazonium chloride is heated with water?
Show answer
[Hint : It gives phenol]
Q37Short answer
Arrange the following compounds in decreasing order of acidity. H2O, ROH, HC ≡ CH
Show answer
[Hint : H2O > ROH > HC ≡≡ CH ]
Q38Short answer
Name the enzymes and write the reactions involved in the preparation of ethanol from sucrose by fermentation.
Show answer
See NCERT textbook for Class XII
Q39Short answer
How can propan-2-one be converted into tert- butyl alcohol?
Show answer
[Hint : Using Grignard reagent]
Q40Short answer
Write the structures of the isomers of alcohols with molecular formula C4H10O. Which of these exhibits optical activity? 159 Alcohols, Phenols and Ethers
Show answer
See NCERT textbook for Class XII
Q41Short answer
Explain why is OH group in phenols more strongly held as compared to OH group in alcohols.
Show answer
See NCERT textbook for Class XII
Q42Short answer
Explain why nucleophilic substitution reactions are not very common in phenols.
Show answer
See NCERT textbook for Class XII
Q43Short answer
Preparation of alcohols from alkenes involves the electrophilic attack on alkene carbon atom. Explain its mechanism.
Show answer
See NCERT textbook for Class XII
Q44Short answer
Explain why is O==C==O nonpolar while R—O—R is polar.
Show answer
See NCERT textbook for Class XII
Q45Short answer
Why is the reactivity of all the three classes of alcohols with conc. HCl and ZnCl2 (Lucas reagent) different?
Show answer
An alcohol reacts with conc. HCl and ZnCl2 (Lucas reagent) to give carbocation. More stable is the carbocation, faster is the reaction.
Q46Short answer
Write steps to carry out the conversion of phenol to aspirin.
Q47Short answer
Nitration is an example of aromatic electrophilic substitution and its rate depends upon the group already present in the benzene ring. Out of benzene and phenol, which one is more easily nitrated and why?
Show answer
Phenol is more easily nitrated than benzene as the presence of —OH group in phenol increases the electron density at ortho and para positions in benzene ring by +R effect. The nitration, being an electrophilic substitution reaction is more facile where the electron density is more.
Q48Short answer
In Kolbe’s reaction, instead of phenol, phenoxide ion is treated with carbon dioxide. Why?
Show answer
Phenoxide ion is more reactive than phenol towards electrophilic aromatic substitution and hence undergoes electrophilic substitution with carbondioxide which is a weak electrophile.
Q49Short answer
Dipole moment of phenol is smaller than that of methanol. Why?
Show answer
In phenol, C—O bond is less polar due to electron-withdrawing effect of benzene ring whereas in methanol, C—O bond is more polar due to electron- releasing effect of —CH3 group.
Q50Short answer
Ethers can be prepared by Williamson synthesis in which an alkyl halide is reacted with sodium alkoxide. Di-tert-butyl ether can’t be prepared by this method. Explain.
Show answer
In tert-butyl halides, elimination is favoured over substitution, so alkene is the only reaction product and ether is not formed.
Q51Short answer
Why is the C—O—H bond angle in alcohols slightly less than the tetrahedral angle whereas the C—O—C bond angle in ether is slightly greater?
Show answer
See NCERT textbook for Class XII.
Q52Short answer
Explain why low molecular mass alcohols are soluble in water.
Show answer
See NCERT textbook for Class XII.
Q53Short answer
Explain why p-nitrophenol is more acidic than phenol.
Show answer
See NCERT textbook for Class XII.
Q54Short answer
Explain why alcohols and ethers of comparable molecular mass have different boiling points?
Show answer
See NCERT textbook for Class XII.
Q55Short answer
The carbon-oxygen bond in phenol is slightly stronger than that in methanol. Why?
Show answer
This is due to the fact that— (i) In phenol, conjugation of unshared electron pair over oxygen with aromatic ring results in partial double bond character in carbon- oxygen bond. (ii) In phenol, oxygen is attached to a sp2 hybridised carbon atom while in methanol, it is attached to a sp3 hyrbidised carbon atom. The bond formed between oxygen and sp2 hybridised carbon is more stable than that formed between oxygen and sp3 hybridised carbon.
Q56Short answer
Arrange water, ethanol and phenol in increasing order of acidity and give reason for your answer.
Show answer
Increasing order of acidity is ethanol < water < phenol. The phenoxide ion obtained after the removal of a proton is stabilised by resonance whereas the ethoxide ion obtained after the removal of a proton is destabilised by ‘+I’ effect of —C2H5 group. Therefore phenol is stronger acid than ethanol. On the other hand ethanol is weaker acid than water because electron releasing —C2H5 group in ethanol inreases the electron density on oxygen and hence the polarity of O—H bond in ethanol decreases which results in the decreasing acidic strength. Hence acidic strength increases in the order given above. IV. Matching Type
Q57Multiple choice
Match the structures of the compounds given in Column I with the name of the compounds given in Column II. Column I Column II (i)
- (a)Hydroquinone (ii)
- (b)Phenetole (iii)
- (c)Catechol (iv)
- (d)o-Cresol (v) (e) Quinone (vi) (f) Resorcinol (g) Anisole
Show answer
(a) Hydroquinone (ii)
(d) o-Cresol (v) (e) Quinone (vi) (f) Resorcinol (g) Anisole
(b) Phenetole (iii)
(c) Catechol (iv)
Q58Multiple choice
Match the starting materials given in Column I with the products formed by these (Column II) in the reaction with HI. Column I Column II (i) CH3—O—CH3
- (a)161 Alcohols, Phenols and Ethers (ii)
- (b)(iii)
- (c)(iv)
- (d)CH3—OH + CH3—I (e) (f) (g)
Show answer
(a) 161 Alcohols, Phenols and Ethers (ii)
(d) CH3—OH + CH3—I (e) (f) (g)
(b) (iii)
(c) (iv)
Q59Multiple choice
Match the items of column I with items of column II. Column I Column II (i) Antifreeze used in car engine
- (a)Neutral ferric chloride (ii) Solvent used in perfumes
- (b)Glycerol (iii) Starting material for picric acid
- (c)Methanol (iv) Wood spirit
- (d)Phenol (v) Reagent used for detection of (e) Ethleneglycol phenolic group (vi) By product of soap industry (f) Ethanol used in cosmetics
Show answer
(a) Neutral ferric chloride (ii) Solvent used in perfumes
(b) Glycerol (iii) Starting material for picric acid
(c) Methanol (iv) Wood spirit
(d) Phenol (v) Reagent used for detection of (e) Ethleneglycol phenolic group (vi) By product of soap industry (f) Ethanol used in cosmetics
Q60Multiple choice
Match the items of column I with items of column II. Column I Column II (i) Methanol
- (a)Conversion of phenol to o-hydroxysalicylic acid (ii) Kolbe’s reaction
- (b)Ethyl alcohol (iii) Williamson’s synthesis
- (c)Conversion of phenol to salicylaldehyde (iv) Conversion of 2° alcohol to ketone
- (d)Wood spirit (v) Reimer-Tiemann reaction (e) Heated copper at 573K (vi) Fermentation (f) Reaction of alkyl halide with sodium alkoxide
Show answer
(a) Conversion of phenol to o-hydroxysalicylic acid (ii) Kolbe’s reaction
(d) Wood spirit (v) Reimer-Tiemann reaction (e) Heated copper at 573K (vi) Fermentation (f) Reaction of alkyl halide with sodium alkoxide
(b) Ethyl alcohol (iii) Williamson’s synthesis
(c) Conversion of phenol to salicylaldehyde (iv) Conversion of 2° alcohol to ketone
Q61Assertion & reason
Assertion (A): Addition reaction of water to but-1-ene in acidic medium yields butan-1-ol
Reason (R): Addition of water in acidic medium proceeds through the formation of primary carbocation.
Show answer
Q62Assertion & reason
Assertion (A): p-nitrophenol is more acidic than phenol.
Reason (R): Nitro group helps in the stabilisation of the phenoxide ion by dispersal of negative charge due to resonance.
Show answer
Q63Assertion & reason
Assertion (A): IUPAC name of the compound is 2-Ethoxy-2-methylethane.
Reason (R): In IUPAC nomenclature, ether is regarded as hydrocarbon derivative in which a hydrogen atom is replaced by —OR or —OAr group [where R = alkyl group and Ar = aryl group]
Show answer
Q64Assertion & reason
Assertion (A): Bond angle in ethers is slightly less than the tetrahedral angle.
Reason (R): There is a repulsion between the two bulky (—R) groups.
Show answer
Q65Assertion & reason
Assertion (A): Boiling points of alcohols and ethers are high.
Reason (R): They can form intermolecular hydrogen-bonding. 163 Alcohols, Phenols and Ethers
Show answer
Q66Assertion & reason
Assertion (A): Like bromination of benzene, bromination of phenol is also carried out in the presence of Lewis acid.
Reason (R): Lewis acid polarises the bromine molecule.
Show answer
Q67Assertion & reason
Assertion (A): o-Nitrophenol is less soluble in water than the m- and p-isomers.
Reason (R): m- and p- Nitrophenols exist as associated molecules.
Show answer
(v)
Q68Assertion & reason
Assertion (A): Ethanol is a weaker acid than phenol.
Reason (R): Sodium ethoxide may be prepared by the reaction of ethanol with aqueous NaOH.
Show answer
Q69Assertion & reason
Assertion (A): Phenol forms 2, 4, 6 – tribromophenol on treatment with Br2 in carbon disulphide at 273K.
Reason (R): Bromine polarises in carbon disulphide.
Show answer
Q70Assertion & reason
Assertion (A): Phenols give o- and p-nitrophenol on nitration with conc. HNO3 and H2SO4 mixture.
Reason (R): —OH group in phenol is o–, p– directing.
Show answer
Q71Long answer
Write the mechanism of the reaction of HI with methoxybenzene.
Show answer
Consult NCERT textbook for Class XII.
Q72Multiple choice
- (a)Name the starting material used in the industrial preparation of phenol.
- (b)Write complete reaction for the bromination of phenol in aqueous and non aqueous medium.
- (c)Explain why Lewis acid is not required in bromination of phenol?
Show answer
Consult NCERT textbook for Class XII.
Q73Long answer
How can phenol be converted to aspirin?
Show answer
Consult NCERT textbook for Class XII.
Q74Long answer
Explain a process in which a biocatalyst is used in industrial preparation of a compound known to you.
Show answer
Consult NCERT textbook for Class XII. 167 Alcohols, Phenols and Ethers