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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Read the Chemistry of Hydrocarbons notesFree MDCAT chapter notes with key terms1,091 questions · page 3 of 55
- A. Angle strain
- B. Torsional strain
- C. Steric strain
- D. Orbital strain
Explanation: The gauche conformation of butane places the two terminal methyl groups close together, causing repulsive van der Waals interactions…
Correct answer: Steric strain- A. 2-methyl octane
- B. n-heptane
- C. iso-octane
- D. 3-methyl octane
Explanation: The octane-number scale assigns 0 to n-heptane and 100 to iso-octane, or 2,2,4-trimethylpentane. Therefore option b is correct.
Correct answer: n-heptane- A. 2 moles of ethane
- B. 1 mole of ethane
- C. 2 moles of butane
- D. 1 mole of butane
Explanation: The Wurtz reaction couples two ethyl groups: 2 C2H5Cl + 2 Na → C2H5-C2H5 + 2 NaCl.
Correct answer: 1 mole of butane- A. acidic
- B. basic
- C. aqueous
- D. dry
Explanation: Wurtz synthesis uses dry ether because sodium reacts vigorously with water and moisture, which would consume the metal and interfere with…
Correct answer: dry- A. methane
- B. ethane
- C. propane
- D. butane
Explanation: Nascent hydrogen reduces ethyl chloride by replacing the chlorine atom with hydrogen: C2H5Cl + 2[H] -> C2H6 + HCl, so ethane is formed.
Correct answer: ethane- A. CO2 and H2O
- B. CH3OH
- C. CO + H2 + C
- D. CO + H2O + C
Explanation: Under controlled limited oxidation, methane can be partially oxidised to methanol: 2CH4 + O2 -> 2CH3OH, rather than being completely…
Correct answer: CH3OH- A. 2
- B. 3
- C. 4
- D. 6
Explanation: Methane, ethane, propane and butane, containing 1 to 4 carbon atoms, are gases at ordinary room temperature because their weak…
Correct answer: 4- A. CaO and KOH
- B. CaO and NaOH
- C. NaOH and Na2O
- D. Na2O and KOH
Explanation: Soda lime is a mixture of sodium hydroxide and calcium oxide, NaOH + CaO; calcium oxide keeps the mixture dry and increases its…
Correct answer: CaO and NaOH- A. alkene
- B. alkyl
- C. aldehyde
- D. saturated hydrocarbon
Explanation: Removing one hydrogen atom from an alkane leaves an alkyl group, written as R-, which has one unpaired valence available for bonding.
Correct answer: alkyl- A. C2H6
- B. C2H4
- C. C2H2
- D. CH4
Explanation: Methane is the principal feedstock for making hydrogen and synthesis gas, which are used to produce ammonia; ammonia then reacts with…
Correct answer: CH4- A. alkane
- B. alkene
- C. alkyne
- D. aldehydes
Explanation: Hydrogenolysis cleaves a carbon-carbon or carbon-heteroatom bond in the presence of hydrogen, and reduction of suitable organic compounds…
Correct answer: alkane- A. iso-alkane
- B. normal-alkane
- C. neo-alkane
- D. branched-alkane
Explanation: An iso-alkane has a methyl branch on the second carbon from the end, giving an isopropyl-type end arrangement such as 2-methylpropane.
Correct answer: iso-alkane- A. 10%
- B. 15%
- C. 20%
- D. 30%
Explanation: Fractional distillation separates crude petroleum into fractions according to boiling range, and gasoline commonly makes up about 20% of…
Correct answer: 20%- A. n-pentane
- B. iso-heptane
- C. iso-octane
- D. n-heptane
Explanation: Straight-chain hydrocarbons knock more readily because their combustion is less smooth and they have lower octane numbers than highly…
Correct answer: n-heptane- A. Al2O3
- B. Fe2O3
- C. Al2O3 and SiO2
- D. Fe2O3 and SiO2
Explanation: Catalytic cracking converts large hydrocarbons into smaller, more useful molecules at comparatively low temperature and pressure using a…
Correct answer: Al2O3 and SiO2- A. earth layer
- B. mountains
- C. sedimentary rocks
- D. rocks
Explanation: Crude oil formed from buried organic matter that underwent decay and geological transformation in sedimentary rocks.
Correct answer: sedimentary rocks- A. animals
- B. fossils
- C. wood
- D. all of the above
Explanation: Coal is a fossil fuel formed mainly from the long-term burial, pressure and heating of ancient plant material, especially wood and…
Correct answer: wood- A. catenation
- B. hybridization
- C. polymerization
- D. solvation
Explanation: Catenation is the ability of carbon atoms to bond with one another repeatedly, forming straight, branched and cyclic chains.
Correct answer: catenation- A. 100
- B. 90
- C. 80
- D. 70
Explanation: 2,2,4-Trimethylpentane is iso-octane, the standard reference fuel assigned an octane number of 100.
Correct answer: 100- A. Isomerization
- B. Adding (C2H5)4 Pb
- C. Adding (CH3)4 Pb
- D. All
Explanation: Octane number can be increased by converting straight-chain hydrocarbons into branched isomers and by using antiknock additives such as…
Correct answer: All