Question 71:
What type of reaction occurs when a primary alcohol is treated with chromic acid?
A) Oxidation
B) Reduction
C) Substitution
D) Elimination
Answer: A) Oxidation
Explanation: The treatment of a primary alcohol with chromic acid results in its oxidation to a carboxylic acid.
Question 72:
Which of the following compounds would have the highest boiling point?
A) Ethanol
B) 1-Butanol
C) 2-Butanol
D) 2-Methyl-2-propanol
Answer: B) 1-Butanol
Explanation: 1-Butanol has the highest boiling point due to its ability to form strong hydrogen bonds and its straight-chain structure, which allows for better packing in the liquid phase compared to branched structures.
Question 73:
What happens when a tertiary alcohol is treated with chromic acid?
A) It is oxidized to a ketone.
B) It remains unchanged.
C) It is oxidized to a carboxylic acid.
D) It is reduced to an alkane.
Answer: B) It remains unchanged.
Explanation: Tertiary alcohols are resistant to oxidation by chromic acid and remain unchanged.
Question 74:
What is the primary function of sodium bisulfite in organic reactions?
A) To act as a reducing agent
B) To act as an oxidizing agent
C) To precipitate and purify carbonyl compounds
D) To dehydrate alcohols
Answer: C) To precipitate and purify carbonyl compounds
Explanation: Sodium bisulfite can react with carbonyl compounds (aldehydes and ketones) to form bisulfite adducts, which are often soluble in water and can be used for purification.
Question 75:
Which of the following is a characteristic of alcohols?
A) They are typically volatile.
B) They have high boiling points compared to hydrocarbons of similar molecular weight.
C) They are weak bases.
D) Both A and B
Answer: D) Both A and B
Explanation: Alcohols are more volatile and have higher boiling points than hydrocarbons of similar molecular weight due to hydrogen bonding.
Question 76:
Which of the following compounds is most likely to undergo nucleophilic attack?
A) Alcohol
B) Ether
C) Aldehyde
D) Alkane
Answer: C) Aldehyde
Explanation: Aldehydes are more electrophilic and susceptible to nucleophilic attack compared to the other compounds listed.
Question 77:
Which type of reaction converts an alcohol to a carbonyl compound?
A) Oxidation
B) Reduction
C) Substitution
D) Elimination
Answer: A) Oxidation
Explanation: Oxidation of alcohols converts them to carbonyl compounds, such as aldehydes or ketones.
Question 78:
Which reagent would you use to convert an alcohol to an alkyl bromide?
A) HBr
B) PBr3
C) SOBr2
D) All of the above
Answer: D) All of the above
Explanation: All of these reagents can be used to convert alcohols to alkyl bromides through nucleophilic substitution reactions.
Question 79:
Which of the following compounds has a hydroxyl (-OH) group directly attached to an aromatic ring?
A) 1-Butanol
B) Aniline
C) Phenol
D) Ethanol
Answer: C) Phenol
Explanation: Phenol has a hydroxyl (-OH) group directly attached to an aromatic ring, while the others do not.
Question 80:
Which of the following compounds would show a positive result in a Lucas test?
A) 1-Butanol
B) 2-Butanol
C) 2-Methyl-2-propanol
D) Both B and C
Answer: D) Both B and C
Explanation: The Lucas test detects secondary and tertiary alcohols. Both 2-butanol and 2-methyl-2-propanol will react to form an alkyl chloride, giving a positive result.
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