JEE Chemistry Alcohols Phenols and Ethers MCQs Set C

Question. Which of the following are correct statement(s) ?
(i) Polar nature of O–H bond is responsible for acidic character of alcohols.
(ii) Acidic strength of alcohols follow the order 1° > 2° > 3°.
(iii) Alcohols are stronger acids than water.
(iv) Alcohols also react as Bronsted base.
(a) (i), (ii) and (iv)
(b) (i), (iii) and (iv)
(c) (i), (ii) and (iii)
(d) (ii), (iii) and (iv)

Answer: A

Question. Read the following statements and choose the correct option.
(i) Ethanol on dehydration at 443 K gives ethene
(ii) Ethanol on dehydration at 413 K gives diethyl ether
(iii) Only primary alcohols on dehydration give ethers.
(iv) Secondary and tertiary alcohols on dehydration give ethers having 2° and 3° carbon attached with O atom.
(a) TTTF
(b) TTFF
(c) TFTF
(d) FTTF

Answer: A

Question. Which of the following statements are correct ?
(i) In phenols, the —OH group is attached to sp² hybridised carbon of an aromatic ring
(ii) The carbon – oxygen bond length (136 pm) in phenol is slightly more than that in methanol
(iii) Partial double bond character is due to the conjugation of unshared electron pair of oxygen with the aromatic ring.
(iv) sp² hybridised state of carbon to which oxygen is attached.
(a) (i), (iii) and (iv)
(b) (i), (ii) and (v)
(c) (i), (ii) and (iii)
(d) (i) and (iv)

Answer: A

Question. Which of the following statements are correct ?
(i) Ethanol mixed with methanol is called denatured alcohol.
(ii) Excess of methanol in body may cause blindness.
(iii) In the body methanol is oxidised to methanoic acid.
(iv) A methanol poisoned patient is treated by giving intravenous injections of ethanoic acid.
(a) (i), (ii) and (iii)
(b) (i) and (v)
(c) (ii), (iii) and (iv)
(d) None of these

Answer: A

Question. Assertion : The bond angle in alcohols is slightly less than the tetrahedral angle.
Reason : In alcohols, the oxygen of –OH group is attached to sp³ hybridized carbon atom.
(a) Assertion is correct, reason is correct; reason is a correct explanation for assertion
(b) Assertion is correct, reason is correct; reason is not a correct explanation for assertion.
(c) Assertion is correct, reason is incorrect
(d) Assertion is incorrect, reason is correct

Answer: A

Question. Assertion : In Lucas test, 3º alcohols react immediately.
Reason : An equimolar mixture of anhyd. ZnCl₂ and conc. HCl is called Lucas reagent.
(a) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
(b) Assertion is correct, reason is incorrect
(c) Assertion is incorrect, reason is correct
(d) Assertion is correct, reason is correct; reason is a correct explanation for assertion

Answer: A

Question. Assertion : Reimer-Tiemann reaction of phenol with CCl₄ in NaOH at 340 K gives salicyclic acid as the major product.
Reason : The reaction occurs through intermediate formation of dichlorocarbene.
(a) Assertion is correct, reason is incorrect.
(b) Assertion is incorrect, reason is correct
(c) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
(d) None of these

Answer: A

Question. Assertion : Phenol is more reactive than benzene towards electrophilic substitution reaction.
Reason : In the case of phenol, the intermediate carbocation is more resonance stabilized.
(a) Assertion is correct, reason is correct; reason is a correct explanation for assertion
(b) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
(c) Assertion is correct, reason is incorrect
(d) Assertion is incorrect, reason is correct.

Answer: A

Question. Assertion : In case of phenol, bromination takes place even in absence of Lewis acid whereas bromination of benzene takes place in presence of Lewis acid like FeBr₃.
Reason : – OH group attached to benzene ring is highly deactivating.
(a)   Assertion is correct, reason is incorrect
(b) Assertion is incorrect, reason is correct
(c) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
(d) Assertion is correct, reason is correct; reason is a correct explanation for assertion

Answer: A

Question. Assertion : Ethers behave as bases in the presence of mineral acids.
Reason : Due to the presence of lone pairs of electrons on oxygen.
(a) Assertion is correct, reason is correct; reason is a correct explanation for assertion
(b) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
(c) Assertion is correct, reason is incorrect
(d) Assertion is incorrect, reason is correct

Answer: A

Question. Assertion : With HI, anisole gives iodobenzene and methyl alcohol.
Reason : Iodide ion combines with smaller group to avoid steric hindrance.
(a) Assertion is incorrect, reason is correct
(b) Assertion is correct, reason is incorrect
(c) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
(d) Assertion is correct, reason is correct; reason is a correct explanation for assertion

Answer: A

Question. Assertion : Ethyl phenyl ether on reaction with HBr form phenol and ethyl bromide.
Reason : Cleavage of C–O bond takes place on ethyloxygen bond due to the more stable phenyl-oxygen bond.
(a) Assertion is correct, reason is incorrect
(b) Assertion is incorrect, reason is correct
(c) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
(d) Assertion is correct, reason is correct; reason is a correct explanation for assertion

Answer: A

Question. Hydration of styrene is carried out in presence of acid as catalyst. The major product is
(a) 1–hydroxy–1–phenylethane.
(b) 2–hydroxy–1–phenylethane.
(c) 2–hydroxy–2–phenylethane
(d) 1–hydroxy–2–phenylethane

Answer: A

Question. The hydroboration of an alkene is carried out, then on oxidation with hydrogen peroxide, the alcohol so obtained is achiral. Possible structure of alkene is (are) :
(i) 2, 3– dimethylbut–2–ene.
(ii) 3, 4–dimethylbut –3–ene.
(iii) 2–methyl–but–2–ene.
(iv) 2–methylpropene.
(a) (i) and (iv)
(b) (iii) and (iv)
(c) (ii) and (iii)
(d) (i) and (iii)

Answer: A

Question.  Mechanism of acid catalysed hydration reaction involves
(i) Protonation of alkene to form carbocation by electrophilic attack of H₃O⁺
(ii) Nucleophilic attack of water on carbocation.
(iii) Deprotonation to form alcohol.
(a) (i), (ii) and (iii)
(b) (i) and (ii)
(c)   (i) and (iii)
(d) (ii) and (iii)

Answer: A

Question. Phenol is less acidic than
(a) acetic acid
(b) acetylene
(c) p-methoxyphenol
(d) ethanol

Answer: A

Question. ClCH₂CH₂OH is stronger acid than CH₃CH₂OH because of:
(a) – I effect of Cl disperses negative charge on O atom to produce more stable anion
(b) None of these
(c) – I effect of Cl disperses negative charge on O atom to produce more stable cation
(d) – I effect of Cl increases negative charge on O atom of alcohol

Answer: A

Question. Which one of the following compounds will be most readily attacked by an electrophile ?
(a) Phenol
(b) Chlorobenzene
(c) Benzene
(d) Toluene

Answer: A

Question.  The reagent used for dehydration of an alcohol is
(a) aluminium oxide
(b) sodium chloride
(c) calcium chloride
(d) phosphorus pentachloride

Answer: A

Question. The alcohol which does not give a stable compound on dehydration is
(a) methyl alcohol
(b) n-Butyl alcohol
(c) ethyl alcohol
(d) n-Propyl alcohol

Answer: A

Question.  Which of the following fact(s) explain as to why p-nitrophenol is more acidic than phenol?
I. –I Effect of nitro group.
II. Greater resonance effect of p-nitrophenoxy group
III. Steric effect of bulky nitro group.
(a) I and II
(b) II and III
(c) I and III
(d) II alone

Answer: A

Question.  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.
(a) (i), (iii) and (iv)
(b) (i) and (iii)
(c) (ii), (iii) and (iv)

Answer: A

Question. Which of the following is most reactive towards aqueous HBr ?
(a) 1-Phenyl-1-propanol
(b) 1-Phenyl-2-propanol
(c) 3-Phenyl-1-propanol
(d) All are equally reactive

Answer: A

Question. The major product of the reaction between tert-butyl chloride and sodium ethoxide is
(a) 2-methylprop-1-ene
(b) 2-butene
(c) 1-butene
(d) ethene

Answer: A

Question. In Williamson synthesis if tertiary alkyl halide is used than
(a) alkene is the only reaction product
(b) a mixture of alkene as a major product and ether as a minor product forms
(c) ether is obtained in poor yield
(d) ether is obtained in good yield

Answer: A