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.
Last updated
Read the Chemistry of Hydrocarbons notesFree MDCAT chapter notes with key terms1,091 questions · page 40 of 55
- A. Halogenation
- B. Hydrogenation
- C. Hydroxylation
- D. Dehydrogenation
Explanation: Hydrogenation of alkenes or alkynes in the presence of nickel at 200-300*C yields alkanes.
Correct answer: Hydrogenation782. Propene can exhibit?
- A. cis-trans isomerism
- B. geometric isomerism
- C. both
- D. none
Explanation: Propene (C3H6) is an example of an alkene, and it has a carbon-carbon double bond.
Correct answer: none- A. low b.p
- B. low vapor pressure
- C. high b.p
- D. high electrical conductivity
Explanation: Organic compounds that are essentially nonpolar and exhibit weak intermolecular forces tend to have low vapor pressure.
Correct answer: low vapor pressure- A. organic compounds can be synthesized from inorganic compounds
- B. organic compounds cannot be synthesized from inorganic compounds
- C. organic compounds can be synthesized by animals
- D. organic compounds can be synthesized by plants
Explanation: Vital force theory, proposed by Jöns Jacob Berzelius in the early 19th century, stated that:Organic compounds originated solely from…
Correct answer: organic compounds cannot be synthesized from inorganic compounds- A. two sigma bonds
- B. two pi bonds
- C. one sigma and one pi bond
- D. one sigma and two pi bond
Explanation: A double bond is formed by the combination of one sigma bond, resulting from head-on orbital overlap, and one pi bond, resulting from…
Correct answer: one sigma and one pi bond- A. knocking
- B. reforming
- C. cracking
- D. both a and c
Explanation: The metallic sound produced by the pre-ignition of fuel in an engine is commonly referred to as knocking.
Correct answer: knocking- A. PbCl2
- B. (C2H5)4Pb
- C. (C2H5)2Pb
- D. all of the above
Explanation: Tetraethyl lead, represented as (C2H5)4Pb, is a well-known anti-knocking agent that was historically used in gasoline.
Correct answer: (C2H5)4Pb- A. metamerism
- B. functional group isomerism
- C. geometric isomerism
- D. positional isomerism
Explanation: Positional isomerism involves isomers that differ in the position of a functional group or substituent on the carbon chain.
Correct answer: positional isomerism- A. Cr2O3 + Al2O3 + SiO2
- B. Raney nickel
- C. Organo-nickel
- D. Ni 250 - 300°C
Explanation: The preparation of benzene from acetylene at 70°C typically employs an organo-nickel catalyst.
Correct answer: Organo-nickel- A. Heating sodium salt of benzoic acid with soda lime
- B. Distilling phenol with Zn dust
- C. Chlorobenzene with NaOH at 360°C & 150 atm.
- D. Hydrolysis of benzene sulfonic acid with superheated steam
Explanation: The mixture of catalysts Cr2O3 + Al2O3 + SiO2 is used when benzene is produced from acetylene at elevated temperatures (500°C).The mixture…
Correct answer: Distilling phenol with Zn dust- A. The rupturing of the benzene ring
- B. Substitution reaction
- C. Addition reaction
- D. No reaction
Explanation: Reacting bromine with benzene in the presence of sunlight will result in bromination through a substitution reaction.
Correct answer: Substitution reaction792. Nitronium ion Is:
- A. NO3 NO
- B. NO
- C. NO2- NO2
- D. NO2
Explanation: The nitronium ion (NO2+) is represented as NO2, where nitrogen is bonded to two oxygen atoms with a positive charge.
Correct answer: NO2- A. alkene
- B. alkyl
- C. aldehyde
- D. saturated hydrocarbon
Explanation: When one hydrogen atom is removed from an alkane, the resulting fragment is called an alkyl group.
Correct answer: alkyl- A. CaO and KOH
- B. decarboxylation
- C. NaOH and Na₂O
- D. Na2O and KOH
Explanation: Soda lime is a mixture of calcium oxide (CaO) and sodium hydroxide (NaOH).
Correct answer: decarboxylation795. R-Mg-Br is called
- A. Grignard reagent
- B. Metallic alkyl halide
- C. Both a & b
- D. Alkyl halide
Explanation: R-Mg-Br is called a Grignard reagent, named after the French chemist François Auguste Victor Grignard who discovered these compounds.
Correct answer: Grignard reagent- A. CO2 and H2O
- B. ethyne
- C. CH3OH
- D. CO + H2O + C
Explanation: Ethyne (acetylene) is the most reactive among the given options. It is highly reactive due to its triple bond, which can easily undergo…
Correct answer: ethyne- A. CnH2n+2
- B. CnH2n-2
- C. CnH2n
- D. CnH2n+1
Explanation: The general formula of an alkyne is CnH2n-2.
Correct answer: CnH2n-2- A. dihalo alkane
- B. alkane
- C. alkynes
- D. both b & c
Explanation: Reactivity due to pi-electrons is present in both alkenes (b) and alkynes (c).
Correct answer: both b & c- A. hydrogen bonding
- B. irregular shape of the molecules
- C. irregular shape of the molecules and strong intermolecular forces
- D. greater molecular size
Explanation: The greater viscosity of honey is primarily attributed to the presence of hydrogen bonding between the molecules in honey, specifically…
Correct answer: hydrogen bonding- A. Chloroform
- B. Acetylene
- C. Di-vinyl acetylene
- D. Chloroprene
Explanation: Synthetic rubber is made by the polymerization of chloroprene (2-chloro-1,3-butadiene).
Correct answer: Chloroprene