Free Chemistry of Hydrocarbons MCQs with Answers
1,091 Chemistry of Hydrocarbons MCQs from Chemistry, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Hydrocarbons are studied through the structures and reactions of alkanes, alkenes, alkynes and aromatic compounds. Coverage includes free radical substitution in alkanes, electrophilic addition to carbon-carbon multiple bonds, benzene substitution, aromatic stability and the difference between addition reactions of alkenes and substitution reactions of benzene.
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- A. Alicyclic
- B. Aliphatic compounds
- C. Aromatic compounds
- D. Acyclic compounds
Explanation: Correct option is C. Aromatic compounds, also known as "mono- and polycyclic aromatic hydrocarbons", are organic compounds containing one…
Correct answer: Aromatic compounds- A. Three triple bonds
- B. Two double bonds
- C. Three double bonds
- D. No multiband
Explanation: Correct option is C. There are 3 double bonds in benzene. Six single bonds between Carbons and Hydrogens, three single bonds between six…
Correct answer: Three double bonds- A. -COOH
- B. -COR
- C. -CN
- D. -OH
Explanation: "-OH" group favors electrophilic attack ortho or para to the substituent while the other group of options doesn't hence the answer is D.
Correct answer: -OH- A. Aldol condensation
- B. Wolf kishner reaction
- C. Wittig reaction
- D. Friedel and craft reaction
Explanation: The reaction in which benzene is reacted with alkyl or acyl halide in the presence of AlCl3 is called Friedel-Craft reaction.
Correct answer: Friedel and craft reaction- A. It has low melting and low boiling points
- B. It has high melting and high boiling points
- C. It has low melting and high boiling points
- D. It has a high solubility in polar solvents
Explanation: Arenes are aromatic compounds (contain benzene rings). Hence, they only possess weak Vander Waal's forces as their intermolecular forces…
Correct answer: It has low melting and low boiling points- A. CH3+
- B. (CH3)2CH+
- C. (CH3)3C+
- D. C2H5+
Explanation: Options A and D are incorrect as they are primary free radicals. Option B is incorrect as it's a secondary free radical.
Correct answer: (CH3)3C+- A. C2H4 + Cl2 -> C2H2Cl2 + H2
- B. C2H6 + Cl2 -> C2H5Cl + HCl
- C. C2H4 + Cl2 -> 2CH3Cl
- D. C2H4 + O2 -> 2CH2Cl + 2HCl
Explanation: Ethane reacts with chlorine by free radical halogenation in the presence of In the presence of sunlight, Cl2 breaks down (homolytically)…
Correct answer: C2H6 + Cl2 -> C2H5Cl + HCl- A. Hydrogen free radical
- B. Chlorine free radical
- C. Hydrogen chloride molecule
- D. Both hydrogen and chlorine free radicals
Explanation: To break the covalent bond between two chlorine atoms, photons of ultraviolet rays are required.
Correct answer: Chlorine free radical- A. Cl2
- B. F2
- C. I2
- D. Br2
Explanation: 'Fluorine' (F2) is the most reactive halogen as it has a small size and high charge density.
Correct answer: F2- A. CHCl3
- B. CCl4
- C. CH2Cl2, CH3Cl
- D. All of these
Explanation: It shows a free radical substitution reaction in which UV light (sunlight) is used to substitute the Hs of the CH4.
Correct answer: All of these- A. Heat
- B. Sunlight
- C. Catalyst
- D. Oxygen
Explanation: 'Ultraviolet light' is simply a source of energy and is being used to break bonds.
Correct answer: Sunlight- A. Nitric acid
- B. Oxygen
- C. Halogen
- D. All of these
Explanation: Reason: Alkanes undergo very few reactions. One of these is the reaction with halogens to form halogenoalkanes.
Correct answer: Halogen- A. Cl2
- B. F2
- C. I2
- D. Br2
Explanation: Fluorine (F) is the most reactive halogen and therefore reacts faster with alkanes in substitution reactions.
Correct answer: F2- A. Heat
- B. Sun light
- C. Catalyst
- D. Oxygen
Explanation: Option B is correct since sunlight is simply a source of energy, and is being used to break bonds.
Correct answer: Sun light- A. Nitric acid
- B. Oxygen
- C. Halogen
- D. All of these options are correct
Explanation: When halogens react with alkanes, the reaction is a free radical reaction.
Correct answer: Halogen- A. Oxidative cleavage
- B. Thermal cracking
- C. Catalytic cracking
- D. Steam cracking
Explanation: A is incorrect as oxidative cleavage does not produce gasoline with a high octane number.A reaction in which a carbon-carbon bond is…
Correct answer: Catalytic cracking- A. Sabatier Sender's Reaction
- B. Hydrogenolysis Reaction
- C. Reduction Reaction
- D. Kolbe's Electrolytic Reaction
Explanation: A is incorrect as Sabatier-Sender's reaction is the reaction in which preparation of ethane is done by the catalytic hydrogenation of…
Correct answer: Kolbe's Electrolytic Reaction- A. Option A
- B. Option B
- C. Option C
- D. Option D
Explanation: There are methyl groups (CH3) on carbons 2, 3 and 4 in option A only.
Correct answer: Option A- A. C2H4 + 3O2 → 2CO2 + 2H2O
- B. CH4 + 2O2 → CO2 + 2H2O
- C. CH4 + 12 O2 = CH3OH (conditions: (Conditions:Cu, 400°C, 200 atm)
- D. C2H2 + 5/2 O2 → 2CO2 + H2O
Explanation: Key points here: The products of combustion are always H2O and C02 2-saturated means those having in which carbon form only single bonds
Correct answer: CH4 + 2O2 → CO2 + 2H2O- A. Mixture of SiO2 and Ni
- B. Mixture of Pt and Cu
- C. Mixture of Fe and MgO
- D. Mixture of SiO2 and Al2O3
Explanation: The catalysts required in catalytic cracking are usually solid acidic catalysts that are a mixture of SiO2 and Al2O3
Correct answer: Mixture of SiO2 and Al2O3