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Free Alcohols MCQs with Answers

154 Alcohols MCQs from Chemistry, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.

Alcohols contain a hydroxyl group attached to a saturated carbon atom and are classified as primary, secondary or tertiary. Their nomenclature, hydrogen bonding, acidity, oxidation, dehydration, reaction with sodium and conversion to haloalkanes are covered, along with the distinction between alcohols and phenols, where the hydroxyl group is attached directly to an aromatic ring.

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154 questions Β· page 8 of 8

141. Which one is least reactive towards reaction with Na?

  • A. HCOOH (Formic Acid)
  • B. CH3CH2COOH (Propanoic Acid)
  • C. CH3OCH3 (Diethyl Ether)
  • D. CH3COOH (Acetic Acid)

Explanation: The correct answer is CH3OCH3 (Diethyl Ether). Diethyl ether does not contain an active hydrogen atom that sodium can displace, unlike…

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Correct answer: CH3OCH3 (Diethyl Ether)

142. The major product of acid catalysed dehydration of 3- pentanol is:

  • A. 1-Pentene
  • B. 3-Pentene
  • C. 2-Methylbutane
  • D. 3-Methylbutane

Explanation: The major product is 2-pentene because it is the most stable alkene formed after carbocation rearrangement and follows Zaitsev's rule.

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Correct answer: 3-Pentene

143. Excess of ethanol is heated with conc: sulphuric acid keeping the temperature 140Β°C. The product formed is

  • A. C2H5OC2H5 + H2O
  • B. C2 H4
  • C. C2 H5 OH
  • D. C2 H6

Explanation: At 140Β°C in the presence of sulfuric acid two molecules of ethanol are dehydrated (lose a molecule of water) to form ether.

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Correct answer: C2H5OC2H5 + H2O

144. Choose reaction that does not require ZnCl3 catalyst:

  • A. A) CH3CH2OH + HCl --> CH3CH2Cl + H2O
  • B. B) CH3CH2OH + HBr --> CH3CH2Br + H2O
  • C. C) CH3CH2OH + HI --> CH3CH2I + H2O
  • D. D) Both B & C

Explanation: The correct answer is Option D The reaction of ethanol with HBr generally does not require a ZnCl2 catalyst because HBr is a more reactive…

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Correct answer: D) Both B & C

145. The alcohol given 𝐢𝐻3 βˆ’ 𝐢𝐻2 βˆ’ 𝐢(𝐢𝐻3)2 βˆ’π‘‚π». If oxidized with a strong oxidizing agent given:

  • A. Aldehyde
  • B. Ketone
  • C. Ether
  • D. None of the above

Explanation: A tertiary alcohol can't form this carbonyl group: the tertiary custom has three single bonds to other C- atoms and one single bond to the…

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Correct answer: None of the above

146. Tertiary alcohols are not oxidized into carbonyl compounds because

  • A. They contain more alkyl group
  • B. They have no alpha-hydrogen
  • C. Suitable oxidizing agent is not available
  • D. None of the above

Explanation: Tertiary alcohols are not oxidized by acidified sodium or potassium dichromate(VI) solution - there is no reaction whatsoever.

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Correct answer: They have no alpha-hydrogen

147. Epoxide obtained from isobutylene is further hydrolyzed in the presence of acid The final product is

  • A. 2,3 - Butanediol
  • B. 1,2 - Butanediol
  • C. 2-Methyl-1,2-Propandiol
  • D. All of them

Explanation: Epoxide obtained from isobutylene is further hydrolyzed in the presence of acid The final product is 2-Methyl-1,2-Propandiol

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Correct answer: 2-Methyl-1,2-Propandiol

148. Amongst the following isomeric alcohols, which one has the highest boiling point.

  • A. 2 - Butanol
  • B. 1 - Butanol
  • C. 2 - Methyle β†’ 2 - Proponal
  • D. All of these have the same boiling point

Explanation: Among the isomeric alcohols you mentioned, 1-butanol has the highest boiling point because it has a longer carbon chain, which allows for…

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Correct answer: 1 - Butanol

149. Ethylene Glycol is oxidized into carbolic Acid by:

  • A. Per Iodic acid
  • B. Lad tetra acetate
  • C. Acidified KMNO4
  • D. Both (A) (B)

Explanation: When periodic acid (HIO4) reacts with ethylene glycol, it actually oxidizes ethylene glycol into a compound called glycolic acid, not…

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Correct answer: Per Iodic acid

150. When ethanol Is taken in excess and temperature is kept 1.40C. On dehydration with conc MO, it gives a molecule of:

  • A. Ethene
  • B. Ether
  • C. Ethyl hydrogen sulphat
  • D. None of the above

Explanation: When ethanol is dehydrated with concentrated sulfuric acid (conc MO) at a temperature of 140Β°C, it undergoes a chemical reaction called…

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Correct answer: Ethene

151. CH3MgBr reacts with CH2O to give:

  • A. 10 Alcohol
  • B. 20 Alcohol
  • C. 30 Alcohol
  • D. Carboxylic acid

Explanation: When CH3MgBr, which is methylmagnesium bromide, reacts with CH2O, which is formaldehyde, it undergoes a nucleophilic addition reaction.

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Correct answer: 10 Alcohol

152. Trimethylene glycol is a:

  • A. Vic - diol
  • B. Gem - diol
  • C. Triol
  • D. None of these

Explanation: Trimethylene glycol, also known as 1,3-propanediol, is a vicinal diol. In a vicinal diol, the hydroxyl (-OH) groups are attached to…

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Correct answer: Vic - diol

153. Which one is an aromatic alcohol:

  • A. Methyl alcohol
  • B. Ethyl alcohol
  • C. Benzyl alcohol
  • D. P - cresol

Explanation: An aromatic alcohol is an alcohol that contains an aromatic ring, such as a benzene ring, with a hydroxyl group (-OH) attached.

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Correct answer: Benzyl alcohol

154. The appearance of cloudiness in the Lucas test for alcohol is due to formation of:

  • A. Alkyl chloride
  • B. Acid chlorides
  • C. Aldehydes
  • D. Ketones

Explanation: The appearance of cloudiness in the Lucas test for alcohols is due to the formation of alkyl chloride.

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Correct answer: Alkyl chloride
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