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 16 of 55
301. The conversion of n-hexane into benzene by heating in the presence of Cr2O3+Al2O3+SiO2 is called
- A. Isomerization
- B. Aromatization
- C. Dealkylation
- D. Rearrangement
Explanation: The process described, where n-hexane is converted into benzene by heating in the presence of Cr2O3, Al2O3, and SiO2 catalysts, is called…
Correct answer: Aromatization- A. It is neutral
- B. Exists only at very high temperatures and low temperature
- C. It is found in everything from sun to quark
- D. All of the above
Explanation: Plasma, often referred to as the fourth state of matter, exhibits unique properties distinct from solids, liquids, and gases.
Correct answer: All of the above- A. Allotropy
- B. Polymorphy
- C. Isomorphy
- D. Anisotropy
Explanation: Allotropy refers to the existence of an element in two or more different forms or allotropes, where each form has different physical or…
Correct answer: Allotropy- A. Al_2 O_3 , SiO_2 , Fe_2 O_3
- B. SiO_2 , K_2 O, Cr_2 O_3
- C. Al_2 O_3 , SiO_2 , Cr_2 O_3
- D. None of these
Explanation: The conversion of n-heptane to benzene is a process called aromatization.
Correct answer: Al_2 O_3 , SiO_2 , Cr_2 O_3- A. Sp³
- B. Sp²
- C. Sp
- D. Sp² and Sp³
Explanation: In benzene, each carbon atom is bonded to three other atoms: two carbon atoms and one hydrogen atom.
Correct answer: Sp²- A. Nitro benzene
- B. Nitro Toluene
- C. Nitro methane
- D. Acrylonitrile
Explanation: The nitration of benzene is a classic electrophilic aromatic substitution reaction.
Correct answer: Nitro benzene- A. Alkyl bromide
- B. Hydrogen bromide
- C. Bromo-phenol
- D. Bromo cyclohexane
Explanation: The reaction of benzene with bromine in the presence of a Lewis acid catalyst, such as FeBr_3 , results in electrophilic aromatic…
Correct answer: Bromo-phenol- A. H_2 O_2
- B. Zn dust
- C. Ethyl bromide
- D. HOCl
Explanation: The preparation of benzene from phenol involves a process called reduction.
Correct answer: Zn dust- A. All of the carbon atoms are sp hybridized.
- B. The carbon-carbon bond lengths are all the same
- C. It has delocalized electrons
- D. The carbon-hydrogen bond lengths are all the same
- E. All twelve atoms lie in the same plane
Explanation: This statement is incorrect. The carbon atoms in benzene are sp<sup>2</sup> hybridized, not sp hybridized.
Correct answer: All of the carbon atoms are sp hybridized.- A. 2
- B. 3
- C. 4
- D. Infinite
Explanation: Dewar benzene is an isomer of benzene with a different structure. It has a bicyclic structure with a three-membered ring fused to a…
Correct answer: 3- A. Benzene
- B. Nitrobenzene
- C. Toluene
- D. Alkene
Explanation: The Friedel-Crafts reaction is a type of electrophilic aromatic substitution reaction that involves the alkylation or acylation of…
Correct answer: Toluene- A. Hexachlorocyclohexane
- B. p-Dichlorobenzene
- C. Benzotrichloride
- D. Benzalchloride
Explanation: The reaction of benzene with chlorine in the presence of ultraviolet light is a free radical halogenation reaction.
Correct answer: Hexachlorocyclohexane- A. 70.3
- B. 80.1
- C. 133
- D. 79.41
Explanation: The boiling point of benzene is 80.1 °C. This relatively high boiling point is due to the strong intermolecular forces present between…
Correct answer: 80.1- A. sp³
- B. sp²
- C. sp
- D. None of these
Explanation: As we discussed before, each carbon atom in benzene forms three sigma bonds (two with other carbon atoms and one with a hydrogen atom).
Correct answer: sp²315. C_6 H_5 is:
- A. Phenyl
- B. Methyl
- C. Ethyl
- D. Hexyl
Explanation: C_6 H_5 represents the phenyl group. It is a benzene ring with one hydrogen atom removed.
Correct answer: Phenyl- A. C_6 H_5 CHO
- B. C_6 H_5 CH_2 O_2 C_6 H_5
- C. C_6 H_5 CH_2 OH
- D. C_6 H_5 N
Explanation: Benzyl alcohol has a benzene ring with a -CH_2 OH group attached to it. The formula C_6 H_5 CH_2 OH accurately represents this structure.
Correct answer: C_6 H_5 CH_2 OH- A. Benzene
- B. Alkene
- C. Alkane
- D. Alcohol
Explanation: When acetylene (C_2 H_2 ) is heated at 300°C, it undergoes a process called trimerization.
Correct answer: Benzene- A. Toluene
- B. Benzene
- C. Phenol
- D. PABA
Explanation: As discussed earlier, the Friedel-Crafts reaction is an electrophilic aromatic substitution reaction commonly used for the alkylation or…
Correct answer: Toluene- A. Propane
- B. Cyclobutane
- C. Cyclopropane
- D. Cyclopropanol
Explanation: A secondary carbon is bonded to two other carbon atoms. In the three-carbon ring of cyclopropane (C3H6).
Correct answer: Cyclopropane- A. Ammonical silver nitrate
- B. Ammoniacal cuprous chloride
- C. Both A and B
- D. None of these
Explanation: Terminal alkynes have a slightly acidic hydrogen on the triple-bonded carbon.
Correct answer: Both A and B