Here below some basic MCQ’s about “Alcohols,Phenols and Ethers structure and reaction” with Answer which is explained in details for exam practice. let’s check one by one.
Question 1:
Which of the following is a primary alcohol?
A) 2-Butanol
B) 1-Butanol
C) 2-Methyl-2-propanol
D) 1-Pentanol
Answer: B) 1-Butanol
Explanation: A primary alcohol has the hydroxyl (-OH) group attached to a carbon atom that is connected to only one other carbon atom. In 1-butanol, the -OH group is attached to the terminal carbon, making it a primary alcohol.
Question 2:
Which reaction would NOT produce an ether?
A) The dehydration of two alcohol molecules
B) The reaction of an alcohol with an alkyl halide in the presence of a base
C) The condensation of a phenol with an aldehyde
D) The Williamson ether synthesis
Answer: C) The condensation of a phenol with an aldehyde
Explanation: While aldehydes can react with phenols, they typically do not form ethers directly. The condensation of a phenol with an aldehyde generally leads to products like benzyl alcohols or phenolic compounds rather than ethers.
Question 3:
Which of the following compounds is classified as a phenol?
A) Ethanol
B) Benzyl alcohol
C) Cresol
D) Cyclohexanol
Answer: C) Cresol
Explanation: Phenols are compounds that contain a hydroxyl group (-OH) directly attached to a benzene ring. Cresol is a methyl-substituted phenol, making it a phenolic compound, while the other options do not have the -OH group bonded to a benzene ring.
Question 4:
What is the primary method for the synthesis of ethers via the Williamson ether synthesis?
A) Electrophilic aromatic substitution
B) Alkylation of phenols
C) Nucleophilic substitution
D) Dehydration of alcohols
Answer: C) Nucleophilic substitution
Explanation: The Williamson ether synthesis involves the nucleophilic substitution reaction where an alkoxide ion acts as a nucleophile and attacks an alkyl halide, resulting in the formation of an ether.
Question 5:
Which statement about phenols is correct?
A) They are weaker acids than alcohols.
B) They can be dehydrated to form alkenes.
C) They are more acidic than alcohols due to resonance stabilization.
D) They cannot undergo oxidation.
Answer: C) They are more acidic than alcohols due to resonance stabilization.
Explanation: Phenols are indeed more acidic than alcohols because the negative charge that forms on the phenoxide ion (when phenol donates a proton) can be delocalized over the aromatic ring through resonance. This stabilization makes phenols more acidic compared to aliphatic alcohols.
Question 6:
Which of the following statements about alcohols is TRUE?
A) All alcohols are soluble in water.
B) Alcohols can act as both acids and bases.
C) Alcohols do not participate in hydrogen bonding.
D) Tertiary alcohols are generally more reactive in oxidation reactions than primary alcohols.
Answer: B) Alcohols can act as both acids and bases.
Explanation: Alcohols can donate a proton (acting as an acid) or accept a proton (acting as a base), making them amphoteric. While some alcohols are soluble in water, not all are, especially longer-chain alcohols. Alcohols participate in hydrogen bonding, and primary alcohols are usually more reactive in oxidation than tertiary ones.
Question 7:
What is the major product when phenol is treated with concentrated H2SO4?
A) Benzene
B) Phenyl sulfate
C) Ethyl phenyl ether
D) No reaction
Answer: B) Phenyl sulfate
Explanation: Concentrated sulfuric acid can protonate phenol, leading to the formation of phenyl sulfate as the major product through electrophilic aromatic substitution.
Question 8:
Which of the following alcohols cannot be oxidized to a carboxylic acid?
A) Ethanol
B) 1-Butanol
C) 2-Butanol
D) 1-Pentanol
Answer: C) 2-Butanol
Explanation: 2-Butanol is a secondary alcohol, which can be oxidized to a ketone but cannot be further oxidized to a carboxylic acid, while primary alcohols can be oxidized to carboxylic acids.
Question 9:
Which reagent is commonly used to convert alcohols to alkyl halides?
A) PCl3
B) K2Cr2O7
C) NaBH4
D) H2SO4
Answer: A) PCl3
Explanation: PCl3 is often used to convert alcohols to alkyl halides through a substitution reaction, forming the corresponding alkyl chloride.
Question 10:
Which of the following is a characteristic reaction of phenols?
A) Formation of Grignard reagents
B) Esterification
C) Electrophilic substitution
D) Dehydrogenation
Answer: C) Electrophilic substitution
Explanation: Phenols readily undergo electrophilic substitution reactions due to the electron-donating effect of the hydroxyl group on the aromatic ring.
Question 11:
Which type of ether is most commonly used as an anesthetic?
A) Diethyl ether
B) Methyl ethyl ether
C) Phenyl ether
D) Tetrahydrofuran
Answer: A) Diethyl ether
Explanation: Diethyl ether has historically been used as an anesthetic due to its volatility and ability to induce anesthesia.
Question 12:
What happens when a phenol is treated with a strong base like NaOH?
A) Formation of an ether
B) Formation of a phenoxide ion
C) Formation of a diol
D) No reaction
Answer: B) Formation of a phenoxide ion
Explanation: When phenol reacts with a strong base like NaOH, it deprotonates to form a phenoxide ion, which is more reactive than phenol.
Question 13:
What is the product of the reaction between a primary alcohol and a carboxylic acid in the presence of an acid catalyst?
A) Ether
B) Ester
C) Aldehyde
D) Ketone
Answer: B) Ester
Explanation: The reaction of a primary alcohol with a carboxylic acid in the presence of an acid catalyst leads to the formation of an ester through a process called esterification.
Question 14:
Which of the following compounds would be classified as a tertiary alcohol?
A) 1-Butanol
B) 2-Butanol
C) 2-Methyl-1-propanol
D) 2-Methyl-2-propanol
Answer: D) 2-Methyl-2-propanol
Explanation: Tertiary alcohols have the -OH group attached to a carbon atom that is connected to three other carbon atoms. In 2-methyl-2-propanol, the -OH group is attached to a carbon that is connected to three other carbons.
Question 15:
Which of the following compounds is an aromatic ether?
A) Dimethyl ether
B) Phenyl ethyl ether
C) Diethyl ether
D) Propylene glycol
Answer: B) Phenyl ethyl ether
Explanation: Phenyl ethyl ether contains a phenyl group bonded to an ether oxygen, making it an aromatic ether. The other options do not contain aromatic groups.
Question 16:
What is the result of the reaction of alcohol with acetic anhydride?
A) Ester
B) Ether
C) Aldehyde
D) Ketone
Answer: A) Ester
Explanation: When an alcohol reacts with acetic anhydride, it forms an acetate ester through an acylation reaction.
Question 17:
Which statement is true about the boiling points of alcohols compared to ethers?
A) Alcohols have lower boiling points than ethers.
B) Alcohols have higher boiling points than ethers due to hydrogen bonding.
C) Ethers and alcohols have similar boiling points.
D) Ethers have higher boiling points than alcohols.
Answer: B) Alcohols have higher boiling points than ethers due to hydrogen bonding.
Explanation: Alcohols can form hydrogen bonds due to the presence of -OH groups, leading to higher boiling points compared to ethers, which cannot hydrogen bond in the same way.
Question 18:
Which of the following compounds is a strong acid?
A) Ethanol
B) Phenol
C) Methanol
D) Tertiary butyl alcohol
Answer: B) Phenol
Explanation: Phenol is more acidic than the other options due to the stabilization of its conjugate base (phenoxide ion) by resonance. Ethanol, methanol, and tertiary butyl alcohol are much weaker acids.
Question 19:
What is the main product of the reaction of 1-butanol with HBr?
A) 1-Bromobutane
B) 2-Bromobutane
C) 1-Butene
D) Butyric acid
Answer: A) 1-Bromobutane
Explanation: The reaction of 1-butanol with HBr results in the substitution of the -OH group with a bromine atom, leading to the formation of 1-bromobutane.
Question 20:
Which of the following is a property of ethers?
A) They are polar solvents.
B) They can form hydrogen bonds with themselves.
C) They have higher boiling points than alcohols.
D) They are generally less reactive than alcohols.
Answer: D) They are generally less reactive than alcohols.
Explanation: Ethers are relatively inert compared to alcohols and do not readily participate in reactions such as oxidation or dehydration.
Question 21:
Which of the following methods can be used to prepare phenol?
A) Hydrolysis of chlorobenzene
B) Reduction of benzaldehyde
C) Nitration of benzene
D) Dehydrogenation of cyclohexanol
Answer: A) Hydrolysis of chlorobenzene
Explanation: Hydrolysis of chlorobenzene in the presence of NaOH or H2O can produce phenol. The other methods do not lead to the formation of phenol.
Question 22:
What type of reaction occurs when a secondary alcohol is oxidized?
A) It forms a ketone.
B) It forms an aldehyde.
C) It remains unchanged.
D) It forms a carboxylic acid.
Answer: A) It forms a ketone.
Explanation: Secondary alcohols are oxidized to ketones, while primary alcohols can be oxidized to aldehydes and further to carboxylic acids.
Question 23:
Which of the following compounds is not soluble in water?
A) Methanol
B) Ethanol
C) Propanol
D) Octanol
Answer: D) Octanol
Explanation: Octanol, being a long-chain alcohol, has a hydrophobic tail that makes it less soluble in water compared to shorter-chain alcohols like methanol, ethanol, and propanol.
Question 24:
What happens when a phenol is subjected to electrophilic nitration?
A) It forms a nitro derivative.
B) It forms an ether.
C) It does not react.
D) It forms an aldehyde.
Answer: A) It forms a nitro derivative.
Explanation: Electrophilic nitration of phenol introduces a nitro group (-NO2) to the aromatic ring, resulting in a nitrophenol compound.
Question 25:
Which of the following compounds can undergo dehydration to form an alkene?
A) Primary alcohol
B) Secondary alcohol
C) Tertiary alcohol
D) All of the above
Answer: D) All of the above
Explanation: All types of alcohols (primary, secondary, and tertiary) can undergo dehydration reactions to form alkenes, although the conditions and products may vary.
Question 26:
What is the primary use of phenol in industry?
A) As a solvent
B) As a disinfectant
C) As a precursor for plastics
D) As a fuel
Answer: C) As a precursor for plastics
Explanation: Phenol is primarily used in the production of plastics, particularly in the synthesis of phenolic resins. It is also used in other applications but is most significant in plastics.
Question 27:
Which of the following is a characteristic of tertiary alcohols?
A) They can be oxidized to aldehydes.
B) They do not react with Jones reagent.
C) They readily undergo dehydration.
D) They are less stable than primary alcohols.
Answer: C) They readily undergo dehydration.
Explanation: Tertiary alcohols are more likely to undergo dehydration reactions to form alkenes due to the stability of the carbocation formed during the process.
Question 28:
Which reagent would you use to distinguish between a primary and a secondary alcohol?
A) KMnO4
B) NaOH
C) HBr
D) AgNO3
Answer: A) KMnO4
Explanation: Potassium permanganate (KMnO4) can oxidize primary alcohols to carboxylic acids and secondary alcohols to ketones, allowing differentiation between them.
Question 29:
Which of the following is true about the boiling points of phenols compared to alcohols?
A) Phenols have lower boiling points than alcohols.
B) Phenols have higher boiling points than alcohols due to hydrogen bonding.
C) Phenols and alcohols have similar boiling points.
D) Phenols have significantly higher boiling points than alcohols.
Answer: B) Phenols have higher boiling points than alcohols due to hydrogen bonding.
Explanation: Like alcohols, phenols can hydrogen bond, but they also have aromatic stabilization, which contributes to higher boiling points compared to non-aromatic alcohols.
Question 30:
Which of the following compounds can form an ether through the Williamson ether synthesis?
A) 1-Hexanol
B) Cyclohexanol
C) Tertiary butyl alcohol
D) Phenol
Answer: A) 1-Hexanol
Explanation: 1-Hexanol can be used in the Williamson ether synthesis as it is a primary alcohol. Tertiary alcohols and phenols are not suitable for this method due to steric hindrance.
Question 31:
What is the product of the reaction between phenol and sodium metal?
A) Sodium phenoxide
B) Ether
C) Alkane
D) Benzene
Answer: A) Sodium phenoxide
Explanation: When phenol reacts with sodium metal, it forms sodium phenoxide through the deprotonation of phenol, which is a characteristic reaction.
Question 32:
Which type of alcohol can be readily converted to an alkene via dehydration?
A) Primary alcohol
B) Secondary alcohol
C) Tertiary alcohol
D) All of the above
Answer: D) All of the above
Explanation: All types of alcohols can undergo dehydration, but tertiary alcohols typically do so more readily due to the stability of the carbocation intermediate.
Question 33:
Which of the following statements about ethers is FALSE?
A) Ethers are generally non-polar.
B) Ethers can form hydrogen bonds with water.
C) Ethers have lower boiling points than alcohols of similar molecular weight.
D) Ethers are more stable than alcohols.
Answer: B) Ethers can form hydrogen bonds with water.
Explanation: Ethers cannot form hydrogen bonds with themselves or water due to the absence of hydrogen attached to an electronegative atom. They are, however, soluble in water due to their polarity.
Question 34:
Which of the following is a method to synthesize ethers?
A) Refluxing an alcohol with an alkyl halide
B) Dehydration of alcohols
C) Williamson ether synthesis
D) Both A and C
Answer: D) Both A and C
Explanation: Both the reaction of alcohols with alkyl halides and the Williamson ether synthesis are common methods for synthesizing ethers.
Question 35:
Which reagent would convert a primary alcohol to an aldehyde?
A) H2SO4
B) KMnO4
C) PCC (Pyridinium chlorochromate)
D) NaBH4
Answer: C) PCC (Pyridinium chlorochromate)
Explanation: PCC is a mild oxidizing agent that selectively oxidizes primary alcohols to aldehydes without further oxidation to carboxylic acids.
Question 36:
What type of reaction occurs when an alcohol reacts with a strong acid like H2SO4?
A) Nucleophilic substitution
B) Dehydration
C) Hydrolysis
D) Reduction
Answer: B) Dehydration
Explanation: When an alcohol reacts with a strong acid like H2SO4, it can undergo dehydration to form an alkene through the elimination of water.
Question 37:
Which of the following compounds is not a phenol?
A) Resorcinol
B) Hydroquinone
C) Cresol
D) Anisole
Answer: D) Anisole
Explanation: Anisole is an ether (methoxybenzene) and does not have the hydroxyl (-OH) group characteristic of phenols, while the other options are phenolic compounds.
Question 38:
Which of the following compounds can be oxidized to a carboxylic acid?
A) 2-Pentanol
B) 1-Butanol
C) 2-Butanol
D) 2-Methyl-2-propanol
Answer: B) 1-Butanol
Explanation: 1-Butanol is a primary alcohol that can be oxidized to a carboxylic acid (butanoic acid), while the others are either secondary alcohols or tertiaries that cannot be oxidized to carboxylic acids.
Question 39:
Which of the following alcohols is the least acidic?
A) Methanol
B) Ethanol
C) 1-Butanol
D) 2-Methyl-2-propanol
Answer: D) 2-Methyl-2-propanol
Explanation: 2-Methyl-2-propanol (tert-butyl alcohol) is the least acidic among the options due to the steric hindrance and stability of its conjugate base, which is less favorable compared to the others.
Question 40:
What is the primary product of the reaction between an alcohol and a carboxylic acid in the presence of sulfuric acid?
A) Ether
B) Ester
C) Alcohol
D) Aldehyde
Answer: B) Ester
Explanation: The reaction between an alcohol and a carboxylic acid in the presence of sulfuric acid produces an ester through a process known as esterification.
Question 41:
Which of the following compounds is a secondary alcohol?
A) 1-Propanol
B) 2-Propanol
C) 2-Methyl-1-propanol
D) 1-Hexanol
Answer: B) 2-Propanol
Explanation: 2-Propanol (isopropyl alcohol) is a secondary alcohol because the -OH group is attached to a carbon that is connected to two other carbon atoms.
Question 42:
Which of the following methods can be used to convert an alcohol into an alkene?
A) Dehydration
B) Reduction
C) Oxidation
D) Halogenation
Answer: A) Dehydration
Explanation: Dehydration of an alcohol involves the elimination of water, resulting in the formation of an alkene.
Question 43:
Which of the following is a characteristic of phenolic compounds?
A) They are always neutral.
B) They are weak acids.
C) They cannot be oxidized.
D) They are soluble in hydrocarbons.
Answer: B) They are weak acids.
Explanation: Phenolic compounds can donate protons (H+) and are therefore classified as weak acids due to the resonance stabilization of their phenoxide ions.
Question 44:
Which reagent can be used to convert an alcohol to a ketone?
A) H2SO4
B) Na2Cr2O7
C) PCC
D) Both B and C
Answer: D) Both B and C
Explanation: Both Na2Cr2O7 (chromic acid) and PCC can oxidize secondary alcohols to ketones.
Question 45:
What happens when a primary alcohol is treated with an excess of potassium permanganate?
A) It remains unchanged.
B) It is oxidized to an aldehyde.
C) It is oxidized to a carboxylic acid.
D) It is reduced to an alkane.
Answer: C) It is oxidized to a carboxylic acid.
Explanation: Excess potassium permanganate can fully oxidize a primary alcohol to a carboxylic acid.
Question 46:
Which of the following compounds would react most readily with a nucleophile?
A) Alcohol
B) Ether
C) Aldehyde
D) Ketone
Answer: C) Aldehyde
Explanation: Aldehydes are more electrophilic than ketones due to less steric hindrance and have a carbonyl carbon that is more susceptible to nucleophilic attack.
Question 47:
Which type of reaction is used to synthesize ethers from alcohols?
A) Substitution
B) Elimination
C) Addition
D) Condensation
Answer: D) Condensation
Explanation: The formation of ethers from two alcohols typically occurs through a condensation reaction, where water is eliminated.
Question 48:
What type of alcohol is most likely to undergo oxidation?
A) Primary
B) Secondary
C) Tertiary
D) All of the above
Answer: A) Primary
Explanation: Primary alcohols are more readily oxidized to aldehydes and further to carboxylic acids, whereas tertiary alcohols resist oxidation.
Question 49:
Which of the following compounds would you expect to be the most soluble in water?
A) Octanol
B) Butanol
C) Ethanol
D) 1-Hexanol
Answer: C) Ethanol
Explanation: Ethanol is a short-chain alcohol, which allows for greater hydrogen bonding with water, making it the most soluble compared to the other options.
Question 50:
Which alcohol is used as an antifreeze agent?
A) Methanol
B) Ethanol
C) Isopropanol
D) Butanol
Answer: A) Methanol
Explanation: Methanol is commonly used as an antifreeze agent due to its low freezing point and ability to lower the freezing point of water.
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.
Question 61:
Which of the following compounds can be synthesized using the Grignard reaction?
A) Aldehyde
B) Ketone
C) Alcohol
D) All of the above
Answer: D) All of the above
Explanation: The Grignard reaction can be used to synthesize aldehydes, ketones, and alcohols by reacting with appropriate electrophiles.
Question 62:
What is the primary role of sulfuric acid in the synthesis of esters?
A) It acts as a nucleophile.
B) It provides a proton to alcohol.
C) It serves as a catalyst to facilitate the reaction.
D) It reacts with the ester to produce an alcohol.
Answer: C) It serves as a catalyst to facilitate the reaction.
Explanation: Sulfuric acid acts as a catalyst in the esterification reaction, helping to increase the reaction rate.
Question 63:
Which of the following is NOT a method of alcohol synthesis?
A) Hydroboration-oxidation of alkenes
B) Reduction of carbonyl compounds
C) Grignard reagent reactions
D) Condensation of two alkyl halides
Answer: D) Condensation of two alkyl halides
Explanation: The condensation of two alkyl halides typically leads to the formation of ethers, not alcohols. The other methods can synthesize alcohols.
Question 64:
Which of the following is an example of a diol?
A) Ethanol
B) Butan-1,3-diol
C) Propan-1-ol
D) Isopropanol
Answer: B) Butan-1,3-diol
Explanation: A diol contains two hydroxyl (-OH) groups, and butan-1,3-diol is a clear example.
Question 65:
Which of the following compounds is the most acidic?
A) Ethanol
B) 2-Butanol
C) Phenol
D) Methanol
Answer: C) Phenol
Explanation: Phenol is the most acidic among the given compounds due to the resonance stabilization of its conjugate base.
Question 66:
What is the product of the oxidation of cyclohexanol?
A) Cyclohexene
B) Cyclohexanone
C) Cyclohexyl chloride
D) Cyclohexane
Answer: B) Cyclohexanone
Explanation: The oxidation of cyclohexanol (a secondary alcohol) leads to the formation of cyclohexanone (a ketone).
Question 67:
Which type of alcohol is most commonly used as a solvent in organic reactions?
A) Primary
B) Secondary
C) Tertiary
D) None of the above
Answer: A) Primary
Explanation: Primary alcohols are often used as solvents in organic reactions due to their reactivity and solubility characteristics.
Question 68:
Which of the following compounds is an example of a branched-chain alcohol?
A) 1-Pentanol
B) 2-Pentanol
C) 2-Methyl-1-butanol
D) 1-Butanol
Answer: C) 2-Methyl-1-butanol
Explanation: 2-Methyl-1-butanol is a branched-chain alcohol due to the presence of a methyl group branching off the main chain.
Question 69:
What happens when a phenol is treated with excess bromine?
A) No reaction occurs.
B) It forms a brominated phenol.
C) It forms an ether.
D) It is oxidized to a ketone.
Answer: B) It forms a brominated phenol.
Explanation: Phenols readily react with excess bromine to form brominated phenol products, typically at multiple positions on the ring.
Question 70:
Which of the following is the correct IUPAC name for CH3-CH(OH)-CH2-CH3?
A) 2-Butanol
B) 3-Butanol
C) 1-Butanol
D) 2-Pentanol
Answer: A) 2-Butanol
Explanation: The correct IUPAC name is 2-butanol, indicating that the hydroxyl group is on the second carbon of the butane chain.
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.
Question 81:
Which of the following is a property of ethers?
A) They are highly polar.
B) They can form hydrogen bonds with themselves.
C) They have higher boiling points than alcohols of similar molecular weight.
D) They are generally unreactive.
Answer: D) They are generally unreactive.
Explanation: Ethers are relatively unreactive compared to alcohols and can be considered stable under many conditions, though they can react with strong acids.
Question 82:
What is the primary product when phenol reacts with acetic anhydride?
A) Acetophenone
B) Anisole
C) Acetic acid
D) Benzene
Answer: A) Acetophenone
Explanation: The reaction of phenol with acetic anhydride produces acetophenone through the acylation of the phenolic hydroxyl group.
Question 83:
What is the main product of the reaction between 1-butanol and HCl?
A) Butyl chloride
B) Butyl ether
C) Butanal
D) Butanoic acid
Answer: A) Butyl chloride
Explanation: The reaction of 1-butanol with HCl results in the substitution of the hydroxyl group by a chlorine atom, yielding butyl chloride.
Question 84:
Which alcohol is formed when 2-methylpropene undergoes hydration?
A) 1-Butanol
B) 2-Butanol
C) 2-Methyl-2-propanol
D) Ethanol
Answer: B) 2-Butanol
Explanation: The hydration of 2-methylpropene via Markovnikov’s rule yields 2-butanol as the main product.
Question 85:
Which of the following compounds can be classified as a primary alcohol?
A) 2-Pentanol
B) 1-Hexanol
C) 2-Methyl-2-butanol
D) Cyclohexanol
Answer: B) 1-Hexanol
Explanation: 1-Hexanol has the -OH group attached to a carbon at the end of the chain, making it a primary alcohol.
Question 86:
What is the product when isopropanol (2-propanol) is oxidized?
A) Propanol
B) Acetone
C) Propylene
D) Propionic acid
Answer: B) Acetone
Explanation: Isopropanol (a secondary alcohol) is oxidized to acetone (a ketone) during the oxidation process.
Question 87:
Which reagent can convert an alcohol to an alkyl iodide?
A) HI
B) PBr3
C) SOCl2
D) Both A and B
Answer: A) HI
Explanation: Hydroiodic acid (HI) can convert alcohols to alkyl iodides through a nucleophilic substitution reaction.
Question 88:
Which of the following compounds is a strong acid?
A) Ethanol
B) Phenol
C) 2-Methyl-2-propanol
D) 1-Pentanol
Answer: B) Phenol
Explanation: Phenol is more acidic than simple alcohols due to the resonance stabilization of its conjugate base (phenoxide ion).
Question 89:
Which of the following is an example of a phenolic antioxidant?
A) BHT (Butylated hydroxytoluene)
B) Tert-Butanol
C) Ethanol
D) Methanol
Answer: A) BHT (Butylated hydroxytoluene)
Explanation: BHT is a synthetic antioxidant used to prevent oxidation in food products and is derived from phenolic compounds.
Question 90:
Which reagent is commonly used to convert an alcohol to a sulfonate ester?
A) TsCl (p-toluenesulfonyl chloride)
B) SOCl2
C) HCl
D) PCl3
Answer: A) TsCl (p-toluenesulfonyl chloride)
Explanation: TsCl is used to convert alcohols into sulfonate esters, making them better leaving groups for further reactions.
Question 91:
Which of the following is a characteristic reaction of phenols?
A) Electrophilic aromatic substitution
B) Nucleophilic substitution
C) Elimination
D) Addition
Answer: A) Electrophilic aromatic substitution
Explanation: Phenols readily undergo electrophilic aromatic substitution due to the electron-donating nature of the hydroxyl group, which activates the aromatic ring.
Question 92:
What type of alcohol can be synthesized from the reduction of an aldehyde?
A) Primary alcohol
B) Secondary alcohol
C) Tertiary alcohol
D) None of the above
Answer: A) Primary alcohol
Explanation: Aldehydes are reduced to primary alcohols, whereas ketones yield secondary alcohols.
Question 93:
Which of the following methods can be used to synthesize ethers?
A) Williamson ether synthesis
B) Alkyl halide and alcohol reaction
C) Dehydration of alcohols
D) All of the above
Answer: D) All of the above
Explanation: All of these methods can be employed to synthesize ethers from appropriate reactants.
Question 94:
Which of the following compounds is an example of a tertiary alcohol?
A) 1-Pentanol
B) 2-Pentanol
C) 2-Methyl-2-butanol
D) 1-Butanol
Answer: C) 2-Methyl-2-butanol
Explanation: 2-Methyl-2-butanol has the -OH group attached to a carbon that is bonded to three other carbon atoms, classifying it as a tertiary alcohol.
Question 95:
What is a common use of phenol in the industry?
A) Fuel
B) Plastic production
C) Antibiotics
D) Food preservation
Answer: B) Plastic production
Explanation: Phenol is widely used in the production of plastics, particularly Bakelite and other phenolic resins.
Question 96:
Which of the following reactions is characteristic of alcohols?
A) Nucleophilic addition
B) Electrophilic addition
C) Nucleophilic substitution
D) Electrophilic substitution
Answer: C) Nucleophilic substitution
Explanation: Alcohols can undergo nucleophilic substitution reactions, particularly when converted to better leaving groups.
Question 97:
What is formed when a phenol is treated with sodium hydroxide?
A) Sodium phenoxide
B) Sodium salicylate
C) Phenyl ether
D) None of the above
Answer: A) Sodium phenoxide
Explanation: The reaction between phenol and sodium hydroxide results in the formation of sodium phenoxide through deprotonation.
Question 98:
Which of the following statements about ethers is TRUE?
A) They are polar compounds.
B) They can form hydrogen bonds with each other.
C) They have higher boiling points than alcohols of similar molecular weight.
D) They are more reactive than alcohols.
Answer: A) They are polar compounds.
Explanation: Ethers are polar due to the electronegative oxygen atom, but they do not form hydrogen bonds with each other.
Question 99:
Which of the following is a property of alcohols?
A) They are flammable.
B) They have low boiling points.
C) They are non-soluble in water.
D) They do not participate in redox reactions.
Answer: A) They are flammable.
Explanation: Alcohols are flammable compounds, but they generally have higher boiling points than hydrocarbons of similar molecular weight and are usually soluble in water due to their hydroxyl groups.
Question 100:
What is the primary product when a secondary alcohol is oxidized?
A) Alcohol
B) Ketone
C) Aldehyde
D) Ether
Answer: B) Ketone
Explanation: The oxidation of a secondary alcohol typically results in the formation of a ketone.
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