Free Alkanes MCQs with Answers
127 Alkanes MCQs from Chemistry, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Alkanes are saturated hydrocarbons containing only carbon-carbon and carbon-hydrogen single bonds, with the general formula CnH2n+2 for open chains. Their structure, isomerism, IUPAC nomenclature, physical properties, combustion, free-radical halogenation and conformations are covered, including the difference between substitution in alkanes and addition in unsaturated hydrocarbons.
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127 questions · page 6 of 7
- A. 40
- B. 100
- C. Zero
- D. 2
Explanation: Octane number means the ability of any fuel to resist knocking when it is ignited in a mixture of air.
Correct answer: 100- 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- A. Cracking
- B. Reforming
- C. Polymerisation
- D. Condensation
Explanation: As we see, just straight-chain alkane is converted into branched-chain alkane, nothing else and this conversion is called Reforming.
Correct answer: Reforming- A. Methanol
- B. Propane
- C. Ethylene
- D. Benzene
Explanation: Upon complete oxidation, propane (C3H8 ) gives 4 moles of water:C3H8+5O2→3CO2+4H2O
Correct answer: Propane- A. Methane
- B. Methylamine
- C. Ethylamine
- D. Methyl chloride
Explanation: When methyl magnesium chloride reacts with ammonia, the product obtained is methane.
Correct answer: Methane- A. C6H14
- B. C6H12
- C. C6H10
- D. C6H0
Explanation: C6H12 follows the formula CnH2n, which is the general formula for cycloalkanes.
Correct answer: C6H12- A. Methane
- B. Methyl amine
- C. Ethyl amine
- D. Methyl chloride
Explanation: CH3-Mg-Cl +NH3 ---------> CH4 + NH2MgCl Grignard reagent/methyl magnesium chloride is basic in nature so it will accept H+ from ammonia…
Correct answer: Methane- A. Consumption of fuel
- B. Price of fuel
- C. The octane number of fueL
- D. Knocking of engine
Explanation: The addition of Pb(C2H5)4 in gasoline reduces knocking in the engine by increasing the octane number of fuel.
Correct answer: Knocking of engine- A. C3H12
- B. C5H16
- C. C6H12
- D. C6H14
Explanation: The formula for 2-methyl pentane is C6H14.
Correct answer: C6H14- A. Polymers
- B. Branched-chain hydrocarbons
- C. Ring hydrocarbons
- D. Branched and ring hydrocarbons
Explanation: Reforming is also called AROMATIZATION and is a process in which open-chain hydrocarbons are converted into branched-chain hydrocarbons
Correct answer: Branched-chain hydrocarbons- A. Reforming
- B. Improving octane number
- C. Adding TEL
- D. All of the above
Explanation: Option D is correct because reforming, improving the octane number, and adding TEL are all methods that help reduce knocking and improve…
Correct answer: All of the above116. Why is the boiling point of n-Pentane about 28'C higher than that of its 2,2-Dimethylpropane isomer?
- A. The small surface area of 2,2-Dimethylpropane leads to weaker intermolecular forces.
- B. 2,2-Dimethylpropane molecules experience repulsive forces.
- C. N-Pentane molecules have difficulty interacting closely with each other.
- D. Molecular shape has no impact on boiling point.
Explanation: The correct answer is A. The boiling point of a hydrocarbon is influenced by the strength of intermolecular forces, which depend on…
Correct answer: The small surface area of 2,2-Dimethylpropane leads to weaker intermolecular forces.- A. Fossil fuels
- B. Renewable sources
- C. Infiinite sources
- D. None of the above
Explanation: Coal, natural gas and petroleum are all generally called fossil fuels and are nonrenewable sources of energy.
Correct answer: Fossil fuels- A. n-heptane
- B. n-octane
- C. 2,3,3-trimethylpentane
- D. 2,2,4-trimethylpentane
Explanation: The correct answer is 2,2,4-trimethylpentane, also known as isooctane. It is assigned an octane number of 100 because it has excellent…
Correct answer: 2,2,4-trimethylpentane- A. Contact process
- B. Fischer-Tropsch (FT) process
- C. Fermentation process
- D. Haber-Bosch process
Explanation: The Fischer-Tropsch process is the correct answer because it involves the conversion of carbon monoxide and hydrogen into hydrocarbons…
Correct answer: Fischer-Tropsch (FT) process- A. CH4 + 2O2 → CO2 + 2H2O + heat
- B. 2CH4 + 3O2 → 2CO2 + 4H2O + heat
- C. CH3 - CH3 + 7O2 → CO2 + 6H2O + heat
- D. 2CH4 + 2O2 → 2CO + 4H2O + heat
Explanation: When oxygen supply is limited, combustion is incomplete, leading to the formation of carbon monoxide (CO) and water (H2O).
Correct answer: 2CH4 + 2O2 → 2CO + 4H2O + heat