Free Alkanes MCQs with Answers

• A. Petrol
• B. Sediment
• C. Rock
• D. Fuel

Explanation: The word petroleum comes from Latin roots: petra means rock and oleum means oil, giving the meaning “rock oil.” Therefore, petra refers to…

• 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…

• 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.

• 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.

• 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…

• 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.

• 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…

• 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…

• 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…

• 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.

• 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…

• 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…

• 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.

• 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…

• 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…

• 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…

• 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.

• 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…

• 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.

• 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.