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 4 of 55
- A. PbCl2
- B. (C2H5)4 Pb
- C. (C2H5)2 Pb
- D. all of the above
Explanation: Tetraethyl lead, (C2H5)4Pb, was historically added to petrol to increase octane rating and reduce engine knocking.
Correct answer: (C2H5)4 Pb62. The metallic sound produced by engine due to the pre-ignition of fuel is called _______________?
- A. knocking
- B. reforming
- C. cracking
- D. a and c
Explanation: Knocking is the metallic sound caused by abnormal, premature or uncontrolled ignition of the fuel-air mixture in an engine.
Correct answer: knocking- A. polymerization
- B. pyrolysis
- C. isomerism
- D. no such process occurs
Explanation: Pyrolysis is the thermal decomposition of a large molecule into smaller molecules in the absence of oxygen; hydrocarbon cracking is a…
Correct answer: pyrolysis- A. n. butane
- B. Ethanol
- C. Ethane
- D. Diethy1 ether
Explanation: Reduction replaces the chlorine atom in ethyl chloride, CH3CH2Cl, with hydrogen: CH3CH2Cl + 2[H] -> CH3CH3 + HCl.
Correct answer: Ethane- A. Ethylene only
- B. Acetaldehyde and Formaldehyde
- C. Propionaldehyde and Formaldehyde
- D. Acetaldehyde only
- E. Acetaldehyde and Oxalic acid
Explanation: Reductive ozonolysis cleaves the double bond of 1-butene, CH2=CH-CH2-CH3, into methanal, HCHO, from the terminal carbon and propanal…
Correct answer: Propionaldehyde and Formaldehyde- A. Ethylene oxide
- B. HCHO
- C. Ethylene glycol
- D. Ethyl alcohol
Explanation: Ethene reacts with ozone to form an ozonide, and hydrolysis of this ozonide cleaves the C=C bond.
Correct answer: HCHO- A. Ozonolysis
- B. Oxidation
- C. Reduction
- D. Hydrogenation
Explanation: Ozonolysis breaks a carbon-carbon double bond and produces carbonyl compounds whose structures reveal which groups were attached to the…
Correct answer: Ozonolysis- A. CnH2n+1
- B. CnH2n+2
- C. CnH2n
- D. CnH2n-2
Explanation: An open-chain alkene with one carbon-carbon double bond has the general formula CnH2n, because the double bond removes two hydrogen atoms…
Correct answer: CnH2n- A. Alkenes Family
- B. Saturated hydrocarbon
- C. Aromatic hydrocarbon
- D. None of These
Explanation: Ethene, C2H4, contains a carbon-carbon double bond and is the simplest member of the alkene homologous series.
Correct answer: Alkenes Family- A. Ethylene oxide
- B. HCHO
- C. Ethylene glycol
- D. Ethyl alcohol
Explanation: Ozonolysis cleaves the C=C bond in ethene, CH2=CH2, and each carbon becomes a methanal molecule, HCHO, after hydrolysis of the ozonide.
Correct answer: HCHO- A. Permanent effect
- B. Operate due to electronegativity difference
- C. temporary effect
- D. None of the above
Explanation: The electromeric effect is a complete temporary transfer of the pi-electron pair of a multiple bond towards one atom when an attacking…
Correct answer: temporary effect- A. Reasonable
- B. no bond reasonable
- C. Inductive effect
- D. Electromeric effect
Explanation: Hyperconjugation is delocalization of electrons from a sigma C-H or C-C bond into an adjacent empty or pi-antibonding orbital.
Correct answer: no bond reasonable- A. Aromatic
- B. Alicyclic
- C. Aliphatic
- D. None of These
Explanation: Cyclopentene is a non-aromatic cyclic hydrocarbon, so it is classified as alicyclic.
Correct answer: Alicyclic- A. polyacetylene
- B. benzene
- C. chloroprene
- D. divinyl acetylene
Explanation: Hydrogen chloride adds across the triple bond of vinylacetylene to produce chloroprene, CH2=CCl-CH=CH2, a conjugated diene used in making…
Correct answer: chloroprene- A. Ni-Cu alloy
- B. Ni-Fe alloy
- C. Ni-Al alloy
- D. Ni-Mg alloy
Explanation: Raney nickel is prepared from a nickel-aluminium alloy by treating it with concentrated sodium hydroxide, which dissolves aluminium and…
Correct answer: Ni-Al alloy- A. alkane
- B. alkene
- C. alkyne
- D. both B & C
Explanation: Both alkenes and alkynes contain pi bonds, and their exposed pi electrons make them more reactive than saturated alkanes in addition…
Correct answer: both B & C- A. Aalkene & H2
- B. alkene & O2
- C. alkene & N2
- D. alkyne & Cl2
Explanation: The Sabatier-Senderens reaction hydrogenates an alkene by adding H2 across its carbon-carbon double bond in the presence of nickel…
Correct answer: Aalkene & H2- A. halogenation
- B. hydroxylation
- C. hydrogenation
- D. hydration
Explanation: Vegetable oils contain unsaturated carbon-carbon bonds, and hydrogenation adds H2 across these bonds in the presence of a catalyst such as…
Correct answer: hydrogenation- A. ethane
- B. ethene
- C. ethyne
- D. methane
Explanation: Ethene is used for artificial fruit ripening because it acts as a plant hormone that initiates and accelerates ripening changes.
Correct answer: ethene- A. less reactivity
- B. addition reactions
- C. substitution reactions
- D. none
Explanation: The pi bond in an unsaturated hydrocarbon is relatively exposed and can break while new sigma bonds form, so unsaturated hydrocarbons…
Correct answer: addition reactions