MCQs-based questions and answers on Hydrocarbons in organic chemistry.
Resonance energy of benzene is
- 100 kJ/mol
- 150 kJ/mol
- 200 kJ/mol
- 300 kJ/mol
Question’s Answer: 150 kJ/mol
Alkaline KMnO4 oxidizes acetylene to which of the following?
- Acetic acid
- Glyoxal
- Oxalic acid
- Ethylene glycol
Question’s Answer: Oxalic acid
The hemolytic fission of hydrocarbon results in the formation of
- Carbocation
- Carbene
- Carboanion
- Free radical
Question’s Answer: Free radical
Which reactions can be used to prepare alkane from an alkyl halide?
- Wurtz reaction
- Kolbe reaction
- Fittig reaction
- None of these
Question’s Answer: Wurtz reaction
Which cannot be prepared by Wurtz reaction?
- C2H6
- C4H10
- C3H8
- CH4
Question’s Answer: CH4
Which alkanes cannot be synthesized by Kolbe reaction of sodium salt of carboxylic acid?
- Butane
- Hexane
- Ethane
- Methane
Question’s Answer: Methane
Cetane is a _________.
- n-Hexane
- n-Hexadecane
- n-Octane
- n-pentadecane
Question’s Answer: n-Hexadecane
Coal is mainly a source of
- Aromatic compounds
- Cyclohexanes
- Inorganic compounds
- Aliphatic compounds
Question’s Answer: Aromatic compounds
Which is not present in crude naphtha?
- Gasoline
- Petroleum ether
- Paraffin wax
- Hexane
Question’s Answer: Paraffin wax
What is an Octane number of iso-octane?
- 70
- Zero
- 1
- 100
Question’s Answer: 100
Petroleum is mainly a source of
- Inorganic compounds
- Aliphatic compounds
- Aromatic compounds
- Cyclohexanes
Question’s Answer: Aliphatic compounds
Gasoline contains hydrocarbons in the range
- C-5 to C-8
- C-12 to C-15
- C-4 to C-6
- C-7 to C-12
Question’s Answer: C-7 to C-12
How Successive alkanes differ?
- CH
- CH2
- CH3
- C2H5
Question’s Answer: CH2
Which reactions can be employed to get unsymmetrical alkanes in good yield?
- Corey-House reaction
- Wurtz reaction
- Birch reaction
- None of A, B, and C
Question’s Answer: Corey-House reaction
Alcoholic solution of caustic potash is a specific reagent for which technique?
- Dehydration
- Hydration
- Dehydrogenation
- Dehydrohalogenation
Question’s Answer: Dehydrohalogenation
According to ____, When an alkyl halide is treated dry ether, a symmetry alkane with Na in dry ether, a symmetry alkane is obtained.
- Wurtz reaction
- Grignard reaction
- Fischer-Tropsch reaction
- None of A, B, and C
Question’s Answer: Wurtz reaction
The reduction of an alkyne to alkene using Lindlar’s catalyst results into
- A mixture obtained by syn and anti-addition of hydrogen
- Anti-addition of hydrogen atoms
- Syn addition of hydrogen atoms
- None of A, B, and C
Question’s Answer: Syn addition of hydrogen atoms
The addition of HCl to 2-pentene gives which of the following?
- 2-chloropentane3
- 2-chloropentyne
- -chloropentane
- 2-chloro-2-methyl butane
Question’s Answer: 3-chloropentane
When propyne is treated with aqueous Hâ‚‚SO4 in the presence of HgSO4, Which is the functional isomer of the major product obtained?
- Propanal
- propan-2-ol
- Propanol
- Acetone
Question’s Answer: Acetone
What is the relative order of stability of carbocations RC=CHâ‚‚, RCH2 and RCH=CH RCH CH?
- RC=CHâ‚‚ < RCHâ‚‚ > RCH== CH
- RC CHâ‚‚ < RCHâ‚‚ < RCH=CH
- RC=CHâ‚‚ > RCHâ‚‚ < RCH=CH
- RC= CHâ‚‚ > RCHâ‚‚ >RCH=CH
Question’s Answer: RC= CH₂ > RCH₂ >RCH=CH
Which is most suitable reagent to distinguish compound (III) from the rest of the compounds?
(I) CH3C=CCH3Â Â Â Â Â Â Â Â Â Â Â Â (II) CH3CH,CH,CH, 3Â Â Â Â Â (III) CH3CH,C=CHÂ Â Â Â Â Â Â Â (IV) CH3-CH=CH-CH3
- Br2/CCI4
- Br2/CH3COOH
- Tollen’s reagent
- Alkaline KMnO4
Question’s Answer: Tollen’s reagent
__________ proved that all the six hydrogen atoms in benzene are equivalent?
- Ladenburg
- Kekule
- Faraday
- Wohler
Question’s Answer: Ladenburg
Each of the following compound aromatic excluding which of the following?
- Benzene
- Cyclopentadienyl cation
- Naphthalenec
- Cyclopentadienyl anion
Question’s Answer: Cyclopentadienyl cation
Sodium propionate on decarboxylation with soda-lime gives ______.
- Propane
- Pentane
- Butane
- Ethane
Question’s Answer: Ethane
Ethyne can be prepared from a single step from
- Calcium carbide
- Ethylene bromide
- Ethylidene bromide
- All of A, B, and C
Question’s Answer: Ethylene bromide
Chlorination of toluene in the presence of light and heat followed by treatment with aqueous NaOH gives _____________ .
- Benzoic acid
- p-cresol
- 2,4-dihydroxy toluene
- o-cresol
Question’s Answer: Benzoic acid
Among the following statements on the nitration of aromatic compounds, the false one is
- The rate of nitration of benzene is almost the same as that of hexadeutero- benzene
- The rate of nitration of toluene is greater than that of benzene
- The rate of nitration of benzene is greater than that of hexadeutero benzene
- Nitration is an electrophilic substitution
Question’s Answer: The rate of nitration of benzene is greater than that of hexadeutero benzene
Nitrobenzene can be prepared from benzene by using a mixture of conc. HNO3 and conc. H2SO4. In the nitrating mixture, as a/an
- Base
- Electrophile
- Oxidizing agent
- Acid
Question’s Answer: Electrophile
The electrophile in the sulphonation of benzene is
- SO2
- SO3H
- HSO4
- SO3
Question’s Answer: SO3
Benzene on ozonolysis yields
- Ethanal
- Acetone
- Glyoxal
- Methanal
Question’s Answer: Glyoxal
Chlorination of an alkane involves the attack of
- A base
- A free radical
- A nucleophile
- An electrophile
Question’s Answer: A free radical
Complete oxidation of ethane yields
- Ethanl
- Ethanol
- CO2 and H2O
- Ethanoic acid
Question’s Answer: CO2 and H2O
Which compounds is liquid at room temperature?
- C4H10
- C15H32
- C3H8
- C20H42
Question’s Answer: C15H32
What is the state of hybridization of carbon in methane ?
- sp
- sp3
- sp2
- dsp2
Question’s Answer: sp3
___________ is the formation of alkane by the action of Zn dust.
- Wittig reaction
- Wurtz raection
- Kolbe reaction
- Frankland’s reaction
Question’s Answer: Frankland’s reaction
Which catalyst is used in the reduction of carbonyl group to -CH2
- Zn dust
- Ni
- Pt
- Z/Hg
Question’s Answer: Z/Hg
Which of the following is the process of heating coal in the absence of air?
- Cracking
- Decarbonization
- Decarboxylation
- Isomerization
Question’s Answer: Decarbonization
The %age of carbon is higher in ______.
- Peat
- Anthracite
- Lignite
- Bituminous
Question’s Answer: Lignite
During distillation of coal tar, anthracene mainly present in.
- Light oil
- Heavy oil
- Middle oil
- Green oil
Question’s Answer: Green oil
(CH3)3CMgCl on reaction with Dâ‚‚O produces
- (CD3) CD
- (CH3) 3 COD
- (CH3) 3 CD
- (CD3) 3 OD
Question’s Answer: (CH3) 3 CD
1-Butyne on oxymercuration-demercuration would give
- Propanol and methanol
- Butanal
- Butanone
- Propanoic acid and formic acid
Question’s Answer: Butanone
Preparation of vegetable ghee involves
- Hydrogenation
- Hydroxylation
- Dehydrogenation
- Halogenation
Question’s Answer: Hydrogenation
Ethyl bromide reacts with Zn and HCl to form
- Ethene
- Propyne
- Ethyne
- Ethane
Question’s Answer: Ethane
The most reactive hydrocarbon is
- Ethene
- Heptane
- Acetylene
- Ethane
Question’s Answer: Ethene
Toluene is o/p-orienting with respect to an electrophilic substitution reaction due to
- +1 effect of the methyl group
- +1 as well as +R effect of the methyl group
- Hyper conjugation between the methyl group and phenyl ring
- +R effect of the methyl group
Question’s Answer: +1 as well as +R effect of the methyl group
The substitution reaction in acetylene is possible by which of the following?
- Na metal
- Ammonical AgNO3
- NaNH2
- All of A, B, and C
Question’s Answer: Ammonical AgNO3
The addition of unsymmetrical reagent to an unsymmetrical alkene is in accordance with the rule of:
- Hund’s rule
- Pauli’s principle
- Anti-Marknownikov’s
- Markownikov’s rule
Question’s Answer: Markownikov’e rule
In the Friedel-Craft acylation, the amount of AICI3 that must be taken is
- More than one equivalent
- One equivalent
- In catalytic amount
- Amount does not matter
Question’s Answer: In catalytic amount
Unsaturated nature of alkene can be detected by
- Decolorisation of bromine water
- Ozonolysis
- Decolorisation of KMnO4 solution
- All of A, B, and C
Question’s Answer: All of A, B, and C
What types of reactions are given in alkanes?
- Addition
- Substitution
- Elimination
- Polymerization
Question’s Answer: Addition
Benzene does not undergo
- Addition
- Substitution
- Elimination
- Polymerization
Question’s Answer: Polymerization
Which could be used as catalyst in Friedal-Craft reaction?
- AICI3
- HNO3
- NaCl
- BeCl2
Question’s Answer: AICI3
During nitration of benzene, which is the active nitrating agent?
- NO3
- NO2
- NOâ‚‚+
- NO
Question’s Answer: NO₂+
Which could be used as electrophile in aromatic substitution?
- Hâ‚‚SO4
- SO3
- SO3+
- HSO4
Question’s Answer: SO3
The C-H bond length in benzene is
- 1.09 Ã…
- 0.99 Ã…
- 1.37 Ã…
- 1.12 Ã…
Question’s Answer: 1.09 Å
Aromatic hydrocarbons undergo
- Electrophilic substitution reactions
- Electrophilic addition reaction
- Nucleophilic addition reaction
- None of A, B, and C
Question’s Answer: Electrophilic substitution reactions
Benzene reacts with sunlight to form excess of chlorine in which of the following?
- Chlorobenzene
- Dichlorobenzene
- Benzene hexachloride
- Trichlorobenzene
Question’s Answer: Benzene hexachloride
Coke is obtained by heating coal in __________ .
- Presence of catalyst
- Presence of air
- Limited supply of air
- Absence of air
Question’s Answer: Absence of air
Which compounds has the maximum octane number?
- 2,2,3-Trimethylpentane
- 2,4-Dimethylhexane
- 2,2,4-Trimethylpentane
- n-Octane
Question’s Answer: 2,2,3-Trimethylpentane
Aromatization of n-heptane yields
- Benzene
- Xylene
- m-Xylene
- Toluene
Question’s Answer: Toluene
Carbonization of coal is carried out by heating coal at a temperature
- 1500°C
- 1000°C
- 500°C
- 2000°C
Question’s Answer: 1000°C
Which compounds show geometrical isomerism?
- Vinyl chloride
- 1,1-Dichloroethene
- Trichloroethene
- 1,2-Dichloroethene
Question’s Answer: 1,2-Dichloroethene
How many chain isomers are possible for an alkane having molecular formula C5H12?
- 3
- 5
- 4
- 2
Question’s Answer: 3
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