Question 51:
Which of the following can be used to test for the presence of phenols?
A) Lucas reagent
B) Bromine water
C) Tollen’s reagent
D) Fehling’s solution
Answer: B) Bromine water
Explanation: Bromine water can be used to test for phenols, as phenols will decolorize bromine water due to the electrophilic bromination reaction.
Question 52:
Which of the following alcohols is most likely to form a stable carbocation?
A) 1-Butanol
B) 2-Butanol
C) 2-Methyl-2-propanol
D) 1-Pentanol
Answer: C) 2-Methyl-2-propanol
Explanation: 2-Methyl-2-propanol is a tertiary alcohol, and tertiary carbocations are more stable than primary or secondary ones due to greater hyperconjugation and inductive effects.
Question 53:
Which of the following will react with NaBH4?
A) Alcohols
B) Aldehydes
C) Ketones
D) Both B and C
Answer: D) Both B and C
Explanation: Sodium borohydride (NaBH4) can reduce both aldehydes and ketones to their corresponding alcohols.
Question 54:
Which of the following statements is TRUE about phenol?
A) It is a strong base.
B) It can be easily oxidized to form carboxylic acids.
C) It can undergo electrophilic substitution.
D) It is a nonpolar compound.
Answer: C) It can undergo electrophilic substitution.
Explanation: Phenol can participate in electrophilic substitution reactions due to the electron-donating nature of the hydroxyl group, enhancing the reactivity of the aromatic ring.
Question 55:
Which of the following is a byproduct of the reaction between an alcohol and an acid anhydride?
A) Water
B) Aldehyde
C) Ether
D) Ester
Answer: A) Water
Explanation: The reaction of an alcohol with an acid anhydride produces an ester and water as a byproduct.
Question 56:
Which of the following reagents can be used to convert an alcohol to a chloroalkane?
A) HCl
B) SOCl2
C) PCl5
D) All of the above
Answer: D) All of the above
Explanation: All of these reagents (HCl, SOCl2, PCl5) can convert alcohols to chloroalkanes through substitution reactions.
Question 57:
What happens when an ether is subjected to strong acid?
A) It remains unchanged.
B) It forms an alcohol.
C) It decomposes to an alkene.
D) It forms an alkyl halide.
Answer: B) It forms an alcohol.
Explanation: Ethers can undergo cleavage in the presence of strong acids, forming alcohols and alkyl halides.
Question 58:
Which of the following will not oxidize to an aldehyde or ketone?
A) Secondary alcohol
B) Primary alcohol
C) Tertiary alcohol
D) None of the above
Answer: C) Tertiary alcohol
Explanation: Tertiary alcohols cannot be oxidized to aldehydes or ketones, while primary and secondary alcohols can be oxidized.
Question 59:
Which of the following compounds is a cyclic ether?
A) Ethylene oxide
B) Diethyl ether
C) Dimethyl ether
D) Anisole
Answer: A) Ethylene oxide
Explanation: Ethylene oxide is a three-membered cyclic ether, while the other options are not cyclic.
Question 60:
What is the mechanism of the dehydration of alcohols to form alkenes?
A) SN1
B) SN2
C) E1
D) E2
Answer: C) E1
Explanation: The dehydration of alcohols typically follows an E1 mechanism, where the formation of a carbocation intermediate occurs before the loss of water.
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