Here below some basic MCQ’s about “Alkanes, Alkenes, Alkynes and Aromatic Hydrocarbons” which is well explained. Let’s check one by one which is given below.
1. Which of the following is the correct IUPAC name of the compound CH3-CH=CH-CH3?
a) 1-Butene
b) But-2-ene
c) 2-Butyne
d) 1-Butyne
Answer: b) But-2-ene
Explanation: The correct IUPAC name is But-2-ene because it is a four-carbon chain (butane) with a double bond between the second and third carbon atoms. The position of the double bond is indicated by the number 2.
2. Which of the following reactions is used to convert an alkene into an alkane?
a) Combustion
b) Hydrogenation
c) Dehydrohalogenation
d) Oxidation
Answer: b) Hydrogenation
Explanation: Alkenes are converted to alkanes by the process of hydrogenation, where hydrogen gas (H₂) is added across the double bond of the alkene in the presence of a metal catalyst like Pt, Pd, or Ni.
3. Which reagent is commonly used for the bromination of alkanes?
a) Br₂/FeBr₃
b) Br₂/UV light
c) HBr
d) Br₂/AlBr₃
Answer: b) Br₂/UV light
Explanation: The bromination of alkanes takes place through a free radical mechanism when Br₂ is exposed to UV light, leading to the formation of brominated alkanes.
4. Which of the following compounds does not show geometrical isomerism?
a) 1-Butene
b) 2-Butene
c) 1,2-Dichloroethene
d) 1-Pentene
Answer: a) 1-Butene
Explanation: 1-Butene does not show geometrical isomerism because the double bond is at the terminal position, leaving no possibility for different spatial arrangements of substituents around the double bond.
5. Which of the following is an example of an aromatic hydrocarbon?
a) Ethane
b) Propene
c) Benzene
d) Butyne
Answer: c) Benzene
Explanation: Benzene is an example of an aromatic hydrocarbon because it has a cyclic structure with alternating double and single bonds, which satisfies Huckel’s rule for aromaticity (4n+2 π electrons).
6. Which of the following alkenes undergoes polymerization most readily?
a) Propene
b) Ethene
c) Butene
d) Pentene
Answer: b) Ethene
Explanation: Ethene (C₂H₄) is the simplest alkene and undergoes polymerization easily to form polyethylene, a widely used polymer.
7. What is the product formed when ethyne (acetylene) reacts with hydrogen chloride?
a) Vinyl chloride
b) Ethyl chloride
c) Ethene
d) Chloroethane
Answer: a) Vinyl chloride
Explanation: Ethyne reacts with HCl to form vinyl chloride (CH₂=CHCl) through the addition of HCl to the triple bond, resulting in a double bond product.
8. Which of the following compounds is the most reactive towards electrophilic substitution reactions?
a) Benzene
b) Toluene
c) Nitrobenzene
d) Phenol
Answer: d) Phenol
Explanation: Phenol is the most reactive towards electrophilic substitution due to the electron-donating effect of the hydroxyl group (-OH), which increases the electron density on the benzene ring, especially at the ortho and para positions.
9. Which of the following statements about alkynes is correct?
a) Alkynes are more reactive than alkenes in electrophilic addition reactions.
b) Alkynes can undergo hydrogenation to form alkenes.
c) Alkynes are generally less acidic than alkanes.
d) Alkynes undergo nucleophilic addition more readily than alkenes.
Answer: b) Alkynes can undergo hydrogenation to form alkenes.
Explanation: Alkynes can be partially hydrogenated to form alkenes by adding hydrogen (H₂) in the presence of a catalyst such as Lindlar’s catalyst.
10. Which of the following processes leads to the formation of an aromatic compound?
a) Cracking of hydrocarbons
b) Dehydrocyclization
c) Halogenation of alkanes
d) Polymerization of alkenes
Answer: b) Dehydrocyclization
Explanation: Dehydrocyclization is a process in which alkanes are converted into aromatic compounds, such as the conversion of hexane to benzene, by removing hydrogen and forming a cyclic structure.
11. Which compound is known as the simplest alkyne?
a) Ethylene
b) Propylene
c) Acetylene
d) Butyne
Answer: c) Acetylene
Explanation: Acetylene (C₂H₂) is the simplest alkyne, consisting of two carbon atoms connected by a triple bond.
12. What is the general formula for alkenes?
a) CnH₂n-2
b) CnH₂n+2
c) CnH₂n
d) CnH₂n-1
Answer: c) CnH₂n
Explanation: The general formula for alkenes is CnH₂n, indicating that for every n carbon atoms, there are 2n hydrogen atoms, with at least one double bond present.
13. Which of the following statements is true about the stability of alkenes?
a) More substituted alkenes are less stable.
b) Less substituted alkenes are more stable.
c) More substituted alkenes are more stable.
d) Alkenes do not have stability considerations.
Answer: c) More substituted alkenes are more stable.
Explanation: More substituted alkenes (such as tetrasubstituted alkenes) are more stable due to hyperconjugation and the inductive effect from alkyl groups.
14. Which reaction is used to test for the presence of unsaturation in hydrocarbons?
a) Bromine water test
b) Litmus test
c) Baeyer’s test
d) Tollen’s test
Answer: a) Bromine water test
Explanation: The bromine water test is used to identify unsaturation in hydrocarbons. When an alkene or alkyne is present, the reddish-brown bromine water decolorizes.
15. What is the hybridization of the carbon atoms in ethyne?
a) sp
b) sp²
c) sp³
d) dsp²
Answer: a) sp
Explanation: In ethyne (C₂H₂), the carbon atoms are sp hybridized due to the presence of a triple bond, which consists of one sigma bond and two pi bonds.
16. Which of the following is a characteristic reaction of aromatic compounds?
a) Addition reactions
b) Substitution reactions
c) Elimination reactions
d) Hydrolysis reactions
Answer: b) Substitution reactions
Explanation: Aromatic compounds predominantly undergo electrophilic substitution reactions, where an electrophile replaces one of the hydrogen atoms on the aromatic ring.
17. Which of the following alkenes can exhibit cis-trans isomerism?
a) 1-Butene
b) 2-Butene
c) 1-Pentene
d) 1-Hexene
Answer: b) 2-Butene
Explanation: 2-Butene can exhibit cis-trans isomerism due to the presence of two different substituents on either side of the double bond, allowing for different spatial arrangements.
18. What type of bond is formed between carbon atoms in an alkyne?
a) Single bond
b) Double bond
c) Triple bond
d) Quadruple bond
Answer: c) Triple bond
Explanation: Alkynes contain a triple bond between carbon atoms, which consists of one sigma bond and two pi bonds.
19. Which of the following compounds is a terminal alkyne?
a) 1-Butyne
b) 2-Butyne
c) 1-Pentyne
d) 3-Hexyne
Answer: a) 1-Butyne
Explanation: 1-Butyne is a terminal alkyne as it has the triple bond located at the end of the carbon chain.
20. What is the main product of the combustion of hydrocarbons?
a) Carbon dioxide and water
b) Carbon monoxide and water
c) Carbon and hydrogen
d) Alkane and alkene
Answer: a) Carbon dioxide and water
Explanation: The complete combustion of hydrocarbons produces carbon dioxide (CO₂) and water (H₂O) as the main products.
21. Which of the following is a characteristic of aromatic compounds?
a) High reactivity
b) Low stability
c) Planar structure
d) Non-planar structure
Answer: c) Planar structure
Explanation: Aromatic compounds have a planar structure which allows for effective overlap of p-orbitals, contributing to their stability and resonance.
22. What is the IUPAC name of the compound C6H5-CH2-CH3?
a) Ethylbenzene
b) Benzyl ethyl
c) Phenethyl
d) Benzene ethane
Answer: a) Ethylbenzene
Explanation: The IUPAC name for C6H5-CH2-CH3 is ethylbenzene, indicating an ethyl group attached to a benzene ring.
23. Which of the following is a key characteristic of alkenes?
a) They cannot undergo addition reactions.
b) They have at least one double bond.
c) They are saturated hydrocarbons.
d) They are less reactive than alkanes.
Answer: b) They have at least one double bond.
Explanation: Alkenes are defined by the presence of at least one double bond between carbon atoms, making them unsaturated hydrocarbons.
24. What type of isomerism can occur in alkenes?
a) Structural isomerism
b) Geometric isomerism
c) Optical isomerism
d) Both a and b
Answer: d) Both a and b
Explanation: Alkenes can exhibit structural isomerism (different connectivity of atoms) and geometric isomerism (cis-trans isomerism) due to restricted rotation around the double bond.
25. Which of the following reactions does not involve the addition of hydrogen?
a) Hydrogenation
b) Hydrohalogenation
c) Halogenation
d) Dehydrogenation
Answer: d) Dehydrogenation
Explanation: Dehydrogenation involves the removal of hydrogen, while hydrogenation, hydrohalogenation, and halogenation all involve the addition of hydrogen or halogens.
26. Which compound can be formed by the hydration of propene?
a) Propanol
b) Butanol
c) Ethanol
d) Acetone
Answer: a) Propanol
Explanation: The hydration of propene in the presence of an acid catalyst leads to the formation of propanol (C₃H₈O), specifically isopropanol (2-propanol).
27. Which of the following has the highest boiling point?
a) Butane
b) 1-Butene
c) 2-Butene
d) 1-Butyne
Answer: d) 1-Butyne
Explanation: 1-Butyne has a higher boiling point compared to butane and alkenes due to the presence of a triple bond, which leads to stronger intermolecular forces.
28. Which of the following statements is true regarding the combustion of aromatic hydrocarbons?
a) Aromatic hydrocarbons burn cleanly without soot.
b) Aromatic hydrocarbons do not produce CO₂.
c) Aromatic hydrocarbons produce soot when burned.
d) Aromatic hydrocarbons do not undergo combustion.
Answer: c) Aromatic hydrocarbons produce soot when burned.
Explanation: The combustion of aromatic hydrocarbons often produces soot due to the incomplete combustion of carbon-rich structures.
29. Which of the following is the correct IUPAC name for 2,3-dimethylpentane?
a) 2,3-Dimethyl-2-pentene
b) 2-Methyl-3-pentene
c) 3,4-Dimethyl-2-pentene
d) 3-Methyl-2-pentene
Answer: a) 2,3-Dimethylpentane
Explanation: The compound is named 2,3-dimethylpentane, indicating that two methyl groups are on the second and third carbon atoms of a pentane chain.
30. What is the product when propene reacts with water in the presence of H₂SO₄?
a) Propanol
b) Propionic acid
c) Ethanol
d) Isopropanol
Answer: d) Isopropanol
Explanation: The reaction of propene with water in the presence of H₂SO₄ results in isopropanol (2-propanol) through Markovnikov’s addition.
31. Which of the following compounds has a cyclic structure?
a) Ethane
b) Cyclopropane
c) Butane
d) Propene
Answer: b) Cyclopropane
Explanation: Cyclopropane is a cyclic compound consisting of three carbon atoms arranged in a ring.
32. Which of the following is not a property of alkanes?
a) Non-polar
b) Saturated
c) Generally unreactive
d) Highly soluble in water
Answer: d) Highly soluble in water
Explanation: Alkanes are non-polar and generally unreactive, and they are not soluble in water due to their hydrophobic nature.
33. Which of the following hydrocarbons can undergo electrophilic aromatic substitution?
a) Ethylene
b) Propane
c) Toluene
d) Cyclobutane
Answer: c) Toluene
Explanation: Toluene, as an aromatic compound, can undergo electrophilic aromatic substitution reactions, while alkenes and alkanes do not.
34. What is the IUPAC name of the compound with the formula C₆H₅-CHO?
a) Benzene
b) Benzaldehyde
c) Benzoic acid
d) Phenol
Answer: b) Benzaldehyde
Explanation: The compound C₆H₅-CHO is named benzaldehyde, which contains a formyl group (-CHO) attached to a benzene ring.
35. Which of the following compounds is a diene?
a) 1-Butene
b) 2-Butyne
c) 1,3-Butadiene
d) Cyclobutene
Answer: c) 1,3-Butadiene
Explanation: 1,3-Butadiene is a compound containing two double bonds, making it a diene.
36. Which of the following compounds exhibits resonance?
a) Ethylene
b) Acetylene
c) Benzene
d) 1-Butene
Answer: c) Benzene
Explanation: Benzene exhibits resonance due to its delocalized π electrons, resulting in equal bond lengths and strengths around the ring.
37. Which reaction involves the addition of hydrogen halides to alkenes?
a) Hydration
b) Hydrogenation
c) Hydrohalogenation
d) Halogenation
Answer: c) Hydrohalogenation
Explanation: Hydrohalogenation involves the addition of hydrogen halides (HX) to alkenes, forming haloalkanes.
38. Which of the following is the product of the catalytic hydrogenation of 1-butyne?
a) Butane
b) Butene
c) Butanol
d) Butadiene
Answer: b) Butene
Explanation: The catalytic hydrogenation of 1-butyne results in butene, as it adds hydrogen across the triple bond, forming a double bond.
39. Which of the following compounds is an example of a secondary alcohol?
a) Methanol
b) Ethanol
c) Isopropanol
d) Butanol
Answer: c) Isopropanol
Explanation: Isopropanol (2-propanol) is a secondary alcohol, as the hydroxyl (-OH) group is attached to a carbon atom that is connected to two other carbon atoms.
40. Which of the following compounds will have the lowest boiling point?
a) Hexane
b) Heptane
c) Octane
d) 2-Methylhexane
Answer: a) Hexane
Explanation: Among the given options, hexane has the lowest boiling point due to its shorter carbon chain length compared to the others.
41. What is the major product when benzene reacts with concentrated HNO₃ and H₂SO₄?
a) Nitrobenzene
b) Benzene sulfonic acid
c) Phenol
d) Benzoic acid
Answer: a) Nitrobenzene
Explanation: The reaction of benzene with concentrated HNO₃ and H₂SO₄ produces nitrobenzene through an electrophilic substitution reaction.
42. Which of the following statements about alkynes is false?
a) Alkynes have at least one triple bond.
b) Alkynes are more acidic than alkanes.
c) Alkynes are saturated hydrocarbons.
d) Alkynes can undergo addition reactions.
Answer: c) Alkynes are saturated hydrocarbons.
Explanation: Alkynes are unsaturated hydrocarbons because they contain at least one triple bond, while saturated hydrocarbons have only single bonds.
43. Which compound is formed from the dehydration of alcohols?
a) Alkene
b) Alkane
c) Alkyne
d) Ether
Answer: a) Alkene
Explanation: The dehydration of alcohols results in the formation of alkenes by removing a water molecule (H₂O).
44. Which of the following compounds is most likely to undergo addition reactions?
a) Ethane
b) Ethylene
c) Acetylene
d) All of the above
Answer: b) Ethylene
Explanation: Ethylene (C₂H₄) is more reactive than ethane and acetylene in addition reactions due to its double bond.
45. Which of the following aromatic compounds is a strong electrophile?
a) Toluene
b) Benzene
c) Nitrobenzene
d) Phenol
Answer: c) Nitrobenzene
Explanation: Nitrobenzene is a strong electrophile due to the electron-withdrawing nitro group (-NO₂) which makes the aromatic ring more susceptible to electrophilic substitution.
46. Which of the following reactions can be used to distinguish between alkanes and alkenes?
a) Addition of Br₂
b) Hydrogenation
c) Dehydrogenation
d) Cracking
Answer: a) Addition of Br₂
Explanation: The addition of Br₂ to alkenes will result in the decolorization of bromine water, while alkanes do not react, making this a good distinguishing test.
47. What is the hybridization of the carbon atoms in 1,3-butadiene?
a) sp
b) sp²
c) sp³
d) dsp²
Answer: b) sp²
Explanation: In 1,3-butadiene, each carbon atom involved in the double bond is sp² hybridized, leading to planar geometry.
48. Which of the following is a characteristic of alkynes?
a) They are all gaseous at room temperature.
b) They contain at least one double bond.
c) They are unsaturated hydrocarbons.
d) They are more stable than alkenes.
Answer: c) They are unsaturated hydrocarbons.
Explanation: Alkynes are classified as unsaturated hydrocarbons because they contain at least one triple bond between carbon atoms.
49. Which of the following compounds cannot undergo oxidation to form a ketone?
a) Propan-2-ol
b) Butan-2-ol
c) Ethanol
d) 2-Pentanone
Answer: c) Ethanol
Explanation: Ethanol can be oxidized to form acetaldehyde but cannot be oxidized to form a ketone since it is a primary alcohol.
50. Which of the following compounds will produce a yellow precipitate when treated with iodine?
a) 1-Butyne
b) Benzene
c) Ethanol
d) Cyclopropane
Answer: a) 1-Butyne
Explanation: 1-Butyne will produce a yellow precipitate of iodoform (CHI₃) when treated with iodine and sodium hydroxide, indicating the presence of a terminal alkyne.
51. Which reaction is characteristic of tertiary alcohols?
a) Oxidation
b) Dehydration
c) Hydrogenation
d) Halogenation
Answer: b) Dehydration
Explanation: Tertiary alcohols undergo dehydration readily to form alkenes due to the stability of the carbocation formed during the reaction.
52. Which of the following compounds has the highest acidity?
a) Ethane
b) Ethyne
c) Ethene
d) Benzene
Answer: b) Ethyne
Explanation: Ethyne (acetylene) is more acidic than ethane and ethene due to the sp hybridization of the carbon atom bonded to the hydrogen, which holds the electrons more tightly.
53. Which of the following compounds is used in the preparation of explosives?
a) Toluene
b) Benzene
c) Aniline
d) Nitrobenzene
Answer: d) Nitrobenzene
Explanation: Nitrobenzene can be used as an intermediate in the synthesis of explosives such as TNT (trinitrotoluene).
54. Which of the following is a characteristic feature of electrophilic aromatic substitution?
a) Addition of an electrophile
b) Addition of a nucleophile
c) Loss of aromaticity
d) None of the above
Answer: a) Addition of an electrophile
Explanation: In electrophilic aromatic substitution, an electrophile adds to the aromatic ring, temporarily disrupting the aromaticity before substitution occurs.
55. Which of the following compounds will react with a strong base to form an alkoxide?
a) Alcohol
b) Ether
c) Alkane
d) Ketone
Answer: a) Alcohol
Explanation: Alcohols can react with strong bases to form alkoxides through deprotonation of the hydroxyl (-OH) group.
56. Which of the following compounds is most stable?
a) 1-Butyne
b) 2-Butyne
c) 1-Butene
d) Ethylene
Answer: b) 2-Butyne
Explanation: 2-Butyne is more stable than 1-butyne due to its internal triple bond, which is less strained than a terminal triple bond.
57. Which of the following has a planar structure?
a) Ethyne
b) Ethylene
c) Propane
d) All of the above
Answer: b) Ethylene
Explanation: Ethylene (C₂H₄) is a planar molecule due to the sp² hybridization of its carbon atoms, while ethyne is linear and propane is tetrahedral.
58. Which of the following compounds can undergo polymerization?
a) Ethylene
b) Ethane
c) Cyclohexane
d) Benzene
Answer: a) Ethylene
Explanation: Ethylene can undergo polymerization to form polyethylene, a common plastic.
59. Which of the following compounds is aromatic?
a) Cyclobutane
b) Cyclohexane
c) Cyclopentadiene
d) Benzene
Answer: d) Benzene
Explanation: Benzene is a classic example of an aromatic compound, characterized by its cyclic structure and resonance.
60. What is the result of the reaction of an alkene with water in the presence of sulfuric acid?
a) Alkane
b) Alcohol
c) Ether
d) Alkyne
Answer: b) Alcohol
Explanation: The reaction of an alkene with water in the presence of sulfuric acid leads to the formation of an alcohol through the process of hydration.
61. What type of reaction occurs when an alkane is treated with bromine in the presence of light?
a) Substitution
b) Addition
c) Elimination
d) Polymerization
Answer: a) Substitution
Explanation: The reaction of an alkane with bromine in the presence of light leads to substitution, where a hydrogen atom is replaced by a bromine atom.
62. Which of the following compounds has a -OH group?
a) Benzene
b) Ethylene
c) Phenol
d) Cyclopropane
Answer: c) Phenol
Explanation: Phenol contains a -OH (hydroxyl) group attached to a benzene ring, making it an aromatic alcohol.
63. Which of the following is an example of a primary alcohol?
a) 2-Butanol
b) 1-Butanol
c) Isopropanol
d) 2-Pentanol
Answer: b) 1-Butanol
Explanation: 1-Butanol is a primary alcohol, as the hydroxyl (-OH) group is attached to a carbon atom that is connected to only one other carbon.
64. Which of the following compounds cannot undergo addition reactions?
a) 1-Butene
b) 2-Butyne
c) Benzene
d) Propylene
Answer: c) Benzene
Explanation: Benzene does not undergo addition reactions due to its stable aromatic structure; it undergoes electrophilic substitution instead.
65. What is the IUPAC name of the compound C₃H₆?
a) Propylene
b) Propane
c) Propyn
d) Butene
Answer: a) Propylene
Explanation: The compound with the formula C₃H₆ is propylene, an alkene with a double bond.
66. What is the main functional group present in aldehydes?
a) Carbonyl group
b) Hydroxyl group
c) Carboxyl group
d) Ether group
Answer: a) Carbonyl group
Explanation: The main functional group in aldehydes is the carbonyl group (C=O), with at least one hydrogen atom attached to the carbonyl carbon.
67. What is the primary product when benzene is treated with chlorine in the presence of iron chloride?
a) Chlorobenzene
b) Benzyl chloride
c) Dichlorobenzene
d) Phenol
Answer: a) Chlorobenzene
Explanation: The reaction of benzene with chlorine in the presence of iron chloride produces chlorobenzene via electrophilic aromatic substitution.
68. Which of the following compounds has a higher boiling point?
a) Butane
b) 1-Butene
c) 2-Butene
d) 1-Butyne
Answer: d) 1-Butyne
Explanation: 1-Butyne has a higher boiling point than butane and the butenes due to the presence of a triple bond, which contributes to stronger intermolecular forces.
69. What is the IUPAC name of the compound with the formula C₆H₅-CH₂OH?
a) Phenol
b) Benzyl alcohol
c) Benzoic acid
d) Toluene
Answer: b) Benzyl alcohol
Explanation: The compound C₆H₅-CH₂OH is named benzyl alcohol, which consists of a benzene ring attached to a CH₂OH group.
70. Which of the following is a characteristic of alkenes?
a) They contain only single bonds.
b) They can undergo addition reactions.
c) They are saturated hydrocarbons.
d) They have a higher boiling point than alkanes.
Answer: b) They can undergo addition reactions.
Explanation: Alkenes are characterized by their ability to undergo addition reactions due to the presence of at least one double bond.
71. Which of the following compounds is a strong nucleophile?
a) Toluene
b) Phenol
c) Acetylene
d) Benzene
Answer: b) Phenol
Explanation: Phenol can act as a strong nucleophile due to the availability of the lone pair on the oxygen atom of the hydroxyl group.
72. Which of the following is the major product when 1-hexene undergoes hydroboration-oxidation?
a) 1-Hexanol
b) 2-Hexanol
c) 3-Hexanol
d) Hexanal
Answer: b) 2-Hexanol
Explanation: The hydroboration-oxidation of 1-hexene results in the formation of 2-hexanol, following Markovnikov’s rule.
73. Which of the following is not an aromatic compound?
a) Naphthalene
b) Toluene
c) Cyclohexane
d) Anisole
Answer: c) Cyclohexane
Explanation: Cyclohexane is a saturated compound with no aromatic properties, while naphthalene, toluene, and anisole are all aromatic.
74. What is the functional group of esters?
a) Carbonyl
b) Hydroxyl
c) Carboxyl
d) Alkoxy
Answer: a) Carbonyl
Explanation: The functional group of esters contains a carbonyl group (C=O) bonded to an alkoxy group (R-O).
75. Which of the following compounds has the highest reactivity towards electrophilic substitution?
a) Benzene
b) Toluene
c) Nitrobenzene
d) Aniline
Answer: d) Aniline
Explanation: Aniline is highly reactive in electrophilic substitution due to the electron-donating amino group (-NH₂), which enhances the electron density on the aromatic ring.
76. Which of the following is a common method for producing alkenes?
a) Hydrogenation
b) Dehydrohalogenation
c) Hydration
d) Hydrohalogenation
Answer: b) Dehydrohalogenation
Explanation: Dehydrohalogenation involves the elimination of a hydrogen halide from alkyl halides to form alkenes.
77. What is the major product when 1-pentene reacts with HBr?
a) 1-Bromopentane
b) 2-Bromopentane
c) 3-Bromopentane
d) 4-Bromopentane
Answer: b) 2-Bromopentane
Explanation: The addition of HBr to 1-pentene follows Markovnikov’s rule, resulting in 2-bromopentane as the major product.
78. Which of the following compounds is least soluble in water?
a) Ethanol
b) 1-Butanol
c) Pentane
d) 2-Pentanol
Answer: c) Pentane
Explanation: Pentane is least soluble in water due to its non-polar nature, while the other alcohols are polar and more soluble.
79. Which of the following compounds is the least reactive in electrophilic aromatic substitution?
a) Toluene
b) Nitrobenzene
c) Aniline
d) Benzene
Answer: b) Nitrobenzene
Explanation: Nitrobenzene is least reactive due to the electron-withdrawing nitro group, which decreases the electron density of the aromatic ring, making it less susceptible to electrophilic attack.
80. What is the main product of the oxidation of primary alcohols?
a) Aldehydes
b) Ketones
c) Carboxylic acids
d) Alcohols
Answer: c) Carboxylic acids
Explanation: Primary alcohols are oxidized to form carboxylic acids upon complete oxidation.
81. Which of the following compounds can act as a Lewis acid?
a) Benzene
b) Ethylene
c) Aluminum chloride
d) Water
Answer: c) Aluminum chloride
Explanation: Aluminum chloride (AlCl₃) can accept a pair of electrons, making it a Lewis acid.
82. What type of isomerism is exhibited by compounds that have the same molecular formula but different structural formulas?
a) Geometric isomerism
b) Optical isomerism
c) Structural isomerism
d) Cis-trans isomerism
Answer: c) Structural isomerism
Explanation: Structural isomerism occurs when compounds have the same molecular formula but differ in the connectivity of their atoms.
83. Which of the following compounds can be produced from the reaction of an alcohol with a carboxylic acid?
a) Ether
b) Ester
c) Ketone
d) Aldehyde
Answer: b) Ester
Explanation: The reaction of an alcohol with a carboxylic acid produces an ester through a process called esterification.
84. Which of the following compounds can undergo hydrogenation?
a) Alkane
b) Alkene
c) Alkyne
d) Both b and c
Answer: d) Both b and c
Explanation: Both alkenes and alkynes can undergo hydrogenation, where hydrogen is added across double or triple bonds.
85. What type of bond is formed between two carbon atoms in a triple bond?
a) One sigma bond and two pi bonds
b) Two sigma bonds and one pi bond
c) Three sigma bonds
d) Three pi bonds
Answer: a) One sigma bond and two pi bonds
Explanation: A triple bond consists of one sigma bond and two pi bonds formed by the overlap of atomic orbitals.
86. Which of the following compounds is not an alkane?
a) Propane
b) Butane
c) Cyclopropane
d) 1-Butene
Answer: d) 1-Butene
Explanation: 1-Butene is an alkene due to the presence of a double bond, whereas the others are alkanes.
87. Which of the following can act as a reducing agent?
a) H₂O
b) NaBH₄
c) Cl₂
d) O₂
Answer: b) NaBH₄
Explanation: Sodium borohydride (NaBH₄) is a common reducing agent used in organic chemistry to reduce ketones and aldehydes.
88. Which of the following is a characteristic of cycloalkanes?
a) They have a linear structure.
b) They are saturated hydrocarbons.
c) They contain at least one double bond.
d) They are unsaturated hydrocarbons.
Answer: b) They are saturated hydrocarbons.
Explanation: Cycloalkanes are saturated hydrocarbons that contain only single bonds, arranged in a cyclic structure.
89. Which of the following compounds contains a carbonyl group?
a) Ether
b) Aldehyde
c) Alcohol
d) Alkane
Answer: b) Aldehyde
Explanation: Aldehydes contain a carbonyl group (C=O) at the end of a carbon chain.
90. Which of the following compounds can be produced from the reaction of a ketone with a Grignard reagent?
a) Alcohol
b) Alkene
c) Ether
d) Aldehyde
Answer: a) Alcohol
Explanation: The reaction of a ketone with a Grignard reagent results in the formation of a tertiary alcohol after hydrolysis.
91. Which of the following compounds is a feature of carboxylic acids?
a) They have a strong basic nature.
b) They contain a carbonyl and a hydroxyl group.
c) They are insoluble in water.
d) They are highly volatile.
Answer: b) They contain a carbonyl and a hydroxyl group.
Explanation: Carboxylic acids contain both a carbonyl group (C=O) and a hydroxyl group (-OH), which gives them their acidic properties.
92. Which of the following is a reaction type that involves the loss of a molecule from a saturated compound?
a) Addition
b) Elimination
c) Substitution
d) Rearrangement
Answer: b) Elimination
Explanation: Elimination reactions involve the loss of a small molecule (such as water or hydrogen halide) from a saturated compound, forming a double or triple bond.
93. What type of reaction occurs when a compound reacts with an oxidizing agent?
a) Reduction
b) Substitution
c) Oxidation
d) Hydrolysis
Answer: c) Oxidation
Explanation: The reaction of a compound with an oxidizing agent results in oxidation, which involves an increase in oxidation state.
94. Which of the following compounds has the lowest pKa value?
a) Acetic acid
b) Formic acid
c) Propanoic acid
d) Butanoic acid
Answer: b) Formic acid
Explanation: Formic acid has the lowest pKa value among the given options, indicating it is the strongest acid.
95. Which of the following can be used to prepare alcohols?
a) Reduction of aldehydes
b) Reduction of ketones
c) Hydrolysis of alkyl halides
d) All of the above
Answer: d) All of the above
Explanation: Alcohols can be prepared by the reduction of aldehydes and ketones, as well as by the hydrolysis of alkyl halides.
96. Which of the following statements about alkanes is true?
a) They are all gaseous at room temperature.
b) They are saturated hydrocarbons.
c) They are very reactive.
d) They contain at least one double bond.
Answer: b) They are saturated hydrocarbons.
Explanation: Alkanes are characterized as saturated hydrocarbons due to their only containing single bonds between carbon atoms.
97. Which of the following compounds can form hydrogen bonds?
a) Ethane
b) Propanol
c) Cyclopropane
d) Toluene
Answer: b) Propanol
Explanation: Propanol can form hydrogen bonds due to the presence of a hydroxyl (-OH) group, which is capable of hydrogen bonding with other molecules.
98. Which of the following reactions produces alkenes?
a) Halogenation
b) Dehydrogenation
c) Hydration
d) Hydrogenation
Answer: b) Dehydrogenation
Explanation: Dehydrogenation involves the removal of hydrogen from a saturated hydrocarbon, resulting in the formation of an alkene.
99. What is the main product of the reaction between a carboxylic acid and an alcohol?
a) Ether
b) Ester
c) Aldehyde
d) Ketone
Answer: b) Ester
Explanation: The reaction of a carboxylic acid with an alcohol produces an ester through the process of esterification.
100. Which of the following compounds is a strong acid?
a) Water
b) Ethanol
c) Acetic acid
d) Hydrochloric acid
Answer: d) Hydrochloric acid
Explanation: Hydrochloric acid (HCl) is a strong acid that completely dissociates in water, making it much stronger than the other options listed.
101. Which of the following is a characteristic property of alcohols?
a) High boiling points
b) Low solubility in water
c) Non-polar nature
d) They do not participate in hydrogen bonding
Answer: a) High boiling points
Explanation: Alcohols have high boiling points compared to hydrocarbons of similar molecular weight due to hydrogen bonding between alcohol molecules.
102. What is the main product when a primary alcohol undergoes oxidation?
a) Ketone
b) Aldehyde
c) Carboxylic acid
d) Ester
Answer: c) Carboxylic acid
Explanation: Primary alcohols can be oxidized to form carboxylic acids upon complete oxidation.
103. Which of the following statements is true regarding phenols?
a) Phenols are stronger acids than alcohols.
b) Phenols do not undergo electrophilic substitution.
c) Phenols cannot form hydrogen bonds.
d) Phenols are completely non-polar.
Answer: a) Phenols are stronger acids than alcohols.
Explanation: Phenols are indeed stronger acids than alcohols because the resulting phenoxide ion is stabilized by resonance.
104. Which of the following is used as a dehydrating agent to convert alcohols to alkenes?
a) H₂O
b) H₂SO₄
c) NaOH
d) HCl
Answer: b) H₂SO₄
Explanation: Sulfuric acid (H₂SO₄) is commonly used as a dehydrating agent in the elimination reaction to convert alcohols into alkenes.
105. Which of the following compounds is a tertiary alcohol?
a) 1-Butanol
b) 2-Butanol
c) 2-Methyl-2-propanol
d) 3-Pentanol
Answer: c) 2-Methyl-2-propanol
Explanation: 2-Methyl-2-propanol (tert-butyl alcohol) is a tertiary alcohol, as the hydroxyl group is attached to a carbon that is bonded to three other carbon atoms.
106. What happens when a secondary alcohol is treated with potassium dichromate (K₂Cr₂O₇)?
a) It gets oxidized to an aldehyde.
b) It gets oxidized to a ketone.
c) It remains unchanged.
d) It gets reduced to an alcohol.
Answer: b) It gets oxidized to a ketone.
Explanation: Secondary alcohols are oxidized by potassium dichromate to form ketones.
107. Which of the following alcohols is most soluble in water?
a) Butanol
b) Propanol
c) Octanol
d) Methanol
Answer: d) Methanol
Explanation: Methanol is the most soluble in water due to its small size and ability to form hydrogen bonds with water.
108. Which reaction involves the conversion of alcohols to ethers?
a) Esterification
b) Dehydration
c) Williamson ether synthesis
d) Hydrolysis
Answer: c) Williamson ether synthesis
Explanation: The Williamson ether synthesis involves the reaction of an alkoxide ion with a primary alkyl halide to form an ether.
109. What is the main difference between phenols and alcohols?
a) Phenols are aromatic compounds, while alcohols are not.
b) Phenols are less acidic than alcohols.
c) Alcohols cannot form hydrogen bonds.
d) Phenols do not have a hydroxyl group.
Answer: a) Phenols are aromatic compounds, while alcohols are not.
Explanation: Phenols contain a hydroxyl group attached to an aromatic ring, while alcohols contain a hydroxyl group attached to a non-aromatic carbon chain.
110. Which alcohol is produced when 2-butanol is dehydrated?
a) 1-Butene
b) 2-Butene
c) 3-Butene
d) 2-Butanol remains unchanged.
Answer: b) 2-Butene
Explanation: Dehydration of 2-butanol primarily produces 2-butene through an elimination reaction.
111. What type of reaction occurs when an alcohol is converted to an alkyl halide?
a) Substitution
b) Addition
c) Elimination
d) Rearrangement
Answer: a) Substitution
Explanation: The conversion of an alcohol to an alkyl halide typically involves a substitution reaction where the hydroxyl group is replaced by a halogen.
112. Which of the following is true about the reactivity of alcohols?
a) Tertiary alcohols are more reactive than primary alcohols.
b) Primary alcohols are more reactive than tertiary alcohols.
c) Alcohols do not undergo substitution reactions.
d) All alcohols are equally reactive.
Answer: a) Tertiary alcohols are more reactive than primary alcohols.
Explanation: Tertiary alcohols are generally more reactive in substitution reactions due to the greater stability of the carbocation formed during the reaction.
113. Which of the following statements is false regarding alcohols?
a) Alcohols can form esters.
b) Alcohols are polar compounds.
c) Alcohols cannot be dehydrated to alkenes.
d) Alcohols can participate in hydrogen bonding.
Answer: c) Alcohols cannot be dehydrated to alkenes.
Explanation: This statement is false because alcohols can indeed be dehydrated to form alkenes through elimination reactions.
114. What type of alcohol is isopropanol?
a) Primary alcohol
b) Secondary alcohol
c) Tertiary alcohol
d) None of the above
Answer: b) Secondary alcohol
Explanation: Isopropanol (2-propanol) is a secondary alcohol, as the hydroxyl group is attached to a carbon that is bonded to two other carbon atoms.
115. What is the main use of ethanol in the industry?
a) As a solvent
b) As a fuel
c) In beverages
d) All of the above
Answer: d) All of the above
Explanation: Ethanol is used in various industries as a solvent, fuel, and in beverages.
116. Which of the following methods can be used to synthesize alcohols?
a) Hydration of alkenes
b) Reduction of aldehydes and ketones
c) Hydrolysis of alkyl halides
d) All of the above
Answer: d) All of the above
Explanation: Alcohols can be synthesized by various methods, including the hydration of alkenes, reduction of aldehydes and ketones, and hydrolysis of alkyl halides.
117. What is the IUPAC name of the compound CH₃-CH(OH)-CH₃?
a) 1-Propyl alcohol
b) 2-Propanol
c) 3-Propanol
d) Isopropyl alcohol
Answer: b) 2-Propanol
Explanation: The compound CH₃-CH(OH)-CH₃ is named 2-propanol, indicating that the hydroxyl group is on the second carbon of the propyl chain.
118. Which of the following alcohols has the lowest boiling point?
a) Ethanol
b) Propanol
c) Butanol
d) Methanol
Answer: d) Methanol
Explanation: Methanol has the lowest boiling point among the options due to its small size and lower molecular weight compared to the others.
119. What type of functional group do alcohols contain?
a) Carbonyl group
b) Hydroxyl group
c) Carboxyl group
d) Amino group
Answer: b) Hydroxyl group
Explanation: Alcohols contain a hydroxyl group (-OH), which is their defining feature.
120. Which of the following is true about the dehydration of alcohols?
a) It results in the formation of carboxylic acids.
b) It produces alkenes.
c) It occurs only in the presence of strong bases.
d) It does not require heat.
Answer: b) It produces alkenes.
Explanation: The dehydration of alcohols typically results in the formation of alkenes through the elimination of water.
121. Which of the following statements is correct about the acidity of alcohols?
a) Primary alcohols are more acidic than phenols.
b) Phenols are more acidic than alcohols.
c) Tertiary alcohols are more acidic than primary alcohols.
d) Alcohols are non-acidic in nature.
Answer: b) Phenols are more acidic than alcohols.
Explanation: Phenols are more acidic than alcohols due to the resonance stabilization of the phenoxide ion, while alcohols are less acidic.
122. Which of the following alcohols will not give a positive iodoform test?
a) Ethanol
b) Isopropanol
c) Methanol
d) 2-Butanol
Answer: c) Methanol
Explanation: Methanol does not give a positive iodoform test because it does not have a methyl group adjacent to the hydroxyl group, which is required for the reaction.
123. Which of the following processes is used to produce methanol on an industrial scale?
a) Hydration of ethene
b) Hydrogenation of carbon monoxide
c) Fermentation of sugars
d) Dehydration of ethanol
Answer: b) Hydrogenation of carbon monoxide
Explanation: Methanol is produced industrially by the hydrogenation of carbon monoxide (CO) using a catalyst under high temperature and pressure.
124. Which of the following alcohols will be oxidized to a carboxylic acid?
a) 2-Propanol
b) Ethanol
c) 2-Methyl-2-propanol
d) Cyclohexanol
Answer: b) Ethanol
Explanation: Ethanol is a primary alcohol and can be oxidized first to an aldehyde and then to a carboxylic acid.
125. Which reagent is commonly used to oxidize primary alcohols to aldehydes?
a) Potassium permanganate (KMnO₄)
b) Pyridinium chlorochromate (PCC)
c) Sodium borohydride (NaBH₄)
d) Lithium aluminium hydride (LiAlH₄)
Answer: b) Pyridinium chlorochromate (PCC)
Explanation: Pyridinium chlorochromate (PCC) is commonly used to oxidize primary alcohols to aldehydes without further oxidation to carboxylic acids.
126. Which of the following statements is true for the Lucas test for alcohols?
a) The test distinguishes between alcohols based on their boiling points.
b) Tertiary alcohols react immediately, forming a cloudy solution.
c) Primary alcohols react faster than secondary alcohols.
d) The test does not work for tertiary alcohols.
Answer: b) Tertiary alcohols react immediately, forming a cloudy solution.
Explanation: In the Lucas test, tertiary alcohols react almost instantly, forming a cloudy solution due to the formation of an alkyl chloride.
127. Which alcohol is used as an antifreeze in automobile engines?
a) Ethanol
b) Methanol
c) Glycerol
d) Ethylene glycol
Answer: d) Ethylene glycol
Explanation: Ethylene glycol is used as an antifreeze in automobile engines due to its ability to lower the freezing point of water.
128. Which of the following alcohols is used in the preparation of biodiesel?
a) Methanol
b) Ethanol
c) Isopropanol
d) Glycerol
Answer: a) Methanol
Explanation: Methanol is commonly used in the transesterification process to convert triglycerides into biodiesel.
129. What is the main product when 1-propanol is heated with concentrated sulfuric acid?
a) 1-Propene
b) Propanal
c) Propanoic acid
d) 1-Butene
Answer: a) 1-Propene
Explanation: When 1-propanol is heated with concentrated sulfuric acid, it undergoes dehydration, forming 1-propene.
130. Which of the following is an example of a polyhydric alcohol?
a) Methanol
b) Ethanol
c) Glycerol
d) Butanol
Answer: c) Glycerol
Explanation: Glycerol (or glycerine) is a polyhydric alcohol, meaning it contains three hydroxyl groups.
131. What is the product when ethanol reacts with acetic acid in the presence of an acid catalyst?
a) Ethyl acetate
b) Acetaldehyde
c) Acetone
d) Ethyl alcohol
Answer: a) Ethyl acetate
Explanation: The reaction between ethanol and acetic acid in the presence of an acid catalyst forms an ester, specifically ethyl acetate.
132. Which of the following is used in the preparation of alcoholic beverages?
a) Fermentation
b) Hydrogenation
c) Dehydration
d) Oxidation
Answer: a) Fermentation
Explanation: Fermentation of sugars is used in the preparation of alcoholic beverages, producing ethanol.
133. Which of the following alcohols is the most toxic when ingested?
a) Methanol
b) Ethanol
c) Propanol
d) Isopropanol
Answer: a) Methanol
Explanation: Methanol is highly toxic when ingested, as it is metabolized to formic acid and formaldehyde, leading to serious poisoning.
134. What is the purpose of the iodine test in alcohol chemistry?
a) To test for the presence of a hydroxyl group
b) To test for the presence of a methyl ketone or alcohol with the structure CH₃CH(OH)-
c) To detect the acidity of alcohols
d) To identify primary alcohols
Answer: b) To test for the presence of a methyl ketone or alcohol with the structure CH₃CH(OH)-
Explanation: The iodoform test detects compounds with the structure CH₃CH(OH)- or methyl ketones, resulting in a yellow precipitate of iodoform.
135. Which of the following alcohols would react fastest with Lucas reagent?
a) 1-Butanol
b) 2-Butanol
c) 2-Methyl-2-propanol
d) 1-Propanol
Answer: c) 2-Methyl-2-propanol
Explanation: Tertiary alcohols like 2-methyl-2-propanol react the fastest with Lucas reagent, producing a cloudy solution almost immediately.
136. Which of the following reactions would produce ethanol?
a) Hydration of ethene
b) Dehydration of ethanol
c) Oxidation of ethanol
d) Reduction of ethanal
Answer: a) Hydration of ethene
Explanation: The hydration of ethene results in the formation of ethanol via the addition of water across the double bond of ethene.
137. What happens when ethanol is heated with potassium permanganate?
a) Ethanol is reduced to acetaldehyde.
b) Ethanol is oxidized to acetic acid.
c) Ethanol undergoes dehydration to form ethene.
d) Ethanol is reduced to methane.
Answer: b) Ethanol is oxidized to acetic acid.
Explanation: Ethanol is oxidized to acetic acid when heated with a strong oxidizing agent like potassium permanganate (KMnO₄).
138. What type of reaction occurs when ethanol reacts with sodium metal?
a) Oxidation
b) Elimination
c) Substitution
d) Redox
Answer: d) Redox
Explanation: When ethanol reacts with sodium, a redox reaction occurs, where ethanol donates hydrogen, forming sodium ethoxide and hydrogen gas.
139. What is the IUPAC name of CH₃OH?
a) Methanol
b) Ethanol
c) Propanol
d) Methanal
Answer: a) Methanol
Explanation: The IUPAC name of CH₃OH is methanol, where “meth-” refers to the single carbon atom and “-anol” indicates the hydroxyl group.
140. Which of the following reagents can be used to reduce an alcohol to an alkane?
a) NaBH₄
b) H₂SO₄
c) Zn/HCl
d) PCC
Answer: c) Zn/HCl
Explanation: The combination of zinc and hydrochloric acid can reduce alcohols to alkanes through a reduction process.
141. Which of the following compounds can be classified as a phenolic compound?
a) Ethanol
b) Butanol
c) Resorcinol
d) Glycerol
Answer: c) Resorcinol
Explanation: Resorcinol is a phenolic compound because it contains a hydroxyl group attached to an aromatic ring.
142. Which of the following is the main use of isopropyl alcohol (2-propanol)?
a) As a fuel
b) As an antiseptic
c) As a solvent for paints
d) All of the above
Answer: d) All of the above
Explanation: Isopropyl alcohol is widely used as an antiseptic, solvent for paints, and can also be used as a fuel.
143. What is the primary factor that affects the boiling point of alcohols?
a) Molecular weight
b) Presence of hydrogen bonding
c) Structure of the carbon chain
d) All of the above
Answer: d) All of the above
Explanation: The boiling point of alcohols is affected by molecular weight, hydrogen bonding, and the structure of the carbon chain.
144. Which type of alcohol can form a stable carbocation during a substitution reaction?
a) Primary alcohol
b) Secondary alcohol
c) Tertiary alcohol
d) All alcohols
Answer: c) Tertiary alcohol
Explanation: Tertiary alcohols can form stable carbocations because the positive charge is stabilized by adjacent carbon atoms.
145. Which alcohol is commonly used as a disinfectant in hospitals?
a) Ethanol
b) Isopropanol
c) Methanol
d) Butanol
Answer: b) Isopropanol
Explanation: Isopropanol (isopropyl alcohol) is widely used as a disinfectant in hospitals due to its effectiveness against bacteria and viruses.
146. What is the effect of increasing the number of hydroxyl groups in an alcohol on its solubility in water?
a) Decreases solubility
b) No effect on solubility
c) Increases solubility
d) Increases boiling point only
Answer: c) Increases solubility
Explanation: Increasing the number of hydroxyl groups in an alcohol generally increases its solubility in water due to enhanced hydrogen bonding.
147. Which of the following statements is true regarding the dehydration of alcohols?
a) It is an addition reaction.
b) It requires the presence of a base.
c) It results in the formation of water.
d) It does not require heat.
Answer: c) It results in the formation of water.
Explanation: The dehydration of alcohols is an elimination reaction that results in the formation of water as one of the products.
148. Which of the following alcohols is a straight-chain alcohol?
a) 2-Pentanol
b) 2-Methyl-2-butanol
c) 1-Butanol
d) 2-Butanol
Answer: c) 1-Butanol
Explanation: 1-Butanol is a straight-chain alcohol, while the others have branches in their carbon chains.
149. Which alcohol can be used to produce a sweet-tasting flavor in food products?
a) Ethanol
b) Methanol
c) Propanol
d) Glycerol
Answer: d) Glycerol
Explanation: Glycerol is often used in food products for its sweet taste and is also a humectant that retains moisture.
150. Which of the following processes is used to convert alcohols into alkyl halides?
a) Halogenation
b) Hydrolysis
c) Dehydration
d) Reduction
Answer: a) Halogenation
Explanation: Halogenation involves the reaction of alcohols with halogens or hydrogen halides to convert them into alkyl halides.
151. Which of the following is NOT a method for the synthesis of alcohols?
a) Hydration of alkenes
b) Reduction of carboxylic acids
c) Reduction of alkyl halides
d) Oxidation of ketones
Answer: d) Oxidation of ketones
Explanation: The oxidation of ketones does not produce alcohols; instead, it leads to further oxidation products.
152. Which reagent is typically used to perform the conversion of alcohols to ethers?
a) Sodium metal
b) Sulfuric acid
c) Sodium borohydride
d) Hydrogen halides
Answer: b) Sulfuric acid
Explanation: Sulfuric acid can be used as a catalyst to promote the dehydration of alcohols to form ethers.
153. Which of the following alcohols would you expect to be the least reactive in a substitution reaction?
a) 1-Butanol
b) 2-Butanol
c) 2-Methyl-2-propanol
d) Ethanol
Answer: a) 1-Butanol
Explanation: 1-Butanol is a primary alcohol and is generally less reactive in substitution reactions compared to secondary or tertiary alcohols.
154. Which of the following compounds can be reduced to form an alcohol?
a) Carboxylic acid
b) Alkene
c) Aldehyde
d) All of the above
Answer: d) All of the above
Explanation: Carboxylic acids, alkenes, and aldehydes can all be reduced to form alcohols under appropriate conditions.
155. Which alcohol is known for being used in the production of antifreeze and as a solvent?
a) Ethanol
b) Methanol
c) Propanol
d) Butanol
Answer: b) Methanol
Explanation: Methanol is commonly used in the production of antifreeze and as a solvent in various industrial applications.
156. What is the role of hydrogen in the reduction of alcohols?
a) To oxidize the alcohol
b) To reduce the alcohol to an alkane
c) To form a ketone
d) To dehydrate the alcohol
Answer: b) To reduce the alcohol to an alkane
Explanation: In the reduction of alcohols, hydrogen is used to convert them into alkanes.
157. Which of the following is an example of a branched-chain alcohol?
a) Butanol
b) Pentanol
c) 2-Pentanol
d) 1-Butanol
Answer: c) 2-Pentanol
Explanation: 2-Pentanol is a branched-chain alcohol due to the presence of a hydroxyl group on the second carbon of the pentane chain.
158. Which of the following statements is true regarding the oxidation of alcohols?
a) Primary alcohols can only be oxidized to aldehydes.
b) Secondary alcohols can be oxidized to either ketones or aldehydes.
c) Tertiary alcohols can be oxidized to ketones.
d) All alcohols can be oxidized to carboxylic acids.
Answer: d) All alcohols can be oxidized to carboxylic acids.
Explanation: While primary alcohols can be oxidized to aldehydes and further to carboxylic acids, secondary alcohols can be oxidized to ketones, and tertiary alcohols can be oxidized only under strong conditions to carboxylic acids.
159. Which alcohol is used in the preparation of rocket fuel?
a) Ethanol
b) Isopropanol
c) Methanol
d) Butanol
Answer: c) Methanol
Explanation: Methanol is often used in the preparation of certain types of rocket fuel due to its high energy content.
160. Which of the following tests can be used to distinguish between primary, secondary, and tertiary alcohols?
a) Iodoform test
b) Lucas test
c) Tollens’ test
d) Silver nitrate test
Answer: b) Lucas test
Explanation: The Lucas test can be used to distinguish between primary, secondary, and tertiary alcohols based on their reactivity with hydrogen halides.
Leave a comment