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 48 of 55
- A. Meta directing and deactivating group
- B. Ortho-para directing and deactivating group
- C. Ortho-para directing and activating group
- D. Ortho directing and activating only
- E. Para directing and deactivating only
Explanation: The explanation for this question will be added soon.
Correct answer: Ortho-para directing and activating group- A. Cyclohexane
- B. Hexane
- C. Phenol
- D. Benzoic Acid
- E. Hexene
Explanation: The explanation for this question will be added soon.
Correct answer: Cyclohexane- A. 2
- B. 3
- C. 6
- D. 4
Explanation: Option A is correct since benzene is a resonance hybrid of these two structures shown in the image: Option B is incorrect since it states…
Correct answer: 2- A. Aliphatic
- B. Aromatic
- C. Alicyclic
- D. None of these
Explanation: Aromatic compounds burn with sooty flame because they have a ring structure of carbon atoms.
Correct answer: Aromatic- A. Naphthalene
- B. Phenanthrene
- C. Anthracene
- D. Triphenylmethane
Explanation: The structure of Triphenylmethane is as follows:
Correct answer: Triphenylmethane- A. Dil HCL
- B. Ethyl alcohol
- C. Acetic acid
- D. Acetyl chloride
Explanation: In aniline, the amino group is an electron-releasing group. It activates the benzene ring towards an electrophilic aromatic substitution…
Correct answer: Acetyl chloride947. Which sequence of reaction conditions should be used to produce the compound below from benzene?
- A. AlCl3 / Cl2 ; H2 / Rh / C
- B. Cl2 / UV light ; H2 / Rh / C
- C. H2 / Rh / C ; AlCl3 / Cl2
- D. HCl ; H2 / Rh / C
Explanation: A would be the answer as we have electrophilic substitution taking place involving the formation of a Cl+ ion which is formed via the…
Correct answer: AlCl3 / Cl2 ; H2 / Rh / C- A. AlCl3
- B. NaOH
- C. Chlorobenzenes
- D. Cumene
Explanation: Sodium benzoate is converted to benzene by heating with a mixture of NaOH and CaO.
Correct answer: NaOH- A. Alkylation
- B. Halogenation
- C. Nitration
- D. Acylation
Explanation: Acetophenone is formed by friedal craft acylation. This reaction involves acylation of benzene with acyl chloride or acyl anhydride
Correct answer: Acylation- A. HSO4-
- B. H2SO4
- C. SO3
- D. HSO3
Explanation: SO3 acts as an electrophile in sulphonation. Sometimes H2SO4 is also seen in equations in place of SO3 because H2SO4 dissociates to give…
Correct answer: SO3- A. Good electrophile
- B. Good nucleophile
- C. Resonance hybrid
- D. Extraordinary stable
Explanation: Benzene is a nucleophile because of its delocalized electrons thus the molecule has electron-rich areas which are frequently attacked by…
Correct answer: Good nucleophile- A. In alkynes to identify the position of triple bond
- B. In arenes to identify the position first substitution
- C. In arenes to identify the position second substituition
- D. In all hydrocarbons to identify the position of functional group
Explanation: Ortho, para, and meta are prefixes used to designate the relative positions of second substituent groups on an aromatic ring in organic…
Correct answer: In arenes to identify the position second substituition953. When the two substitutions are different in arenes, they are put in which of the following order?
- A. Numerically
- B. Alphabetically
- C. Alphanumerically
- D. None of these options is correct
Explanation: The substituents in arenes are put in alphabetical order when they are different.
Correct answer: Alphabetically- A. Low melting and low boiling points
- B. High melting and high boiling points
- C. Low melting and high boiling points
- D. High solubility in polar solvents
Explanation: OPTION A: Arenes are compounds that contain benzene ring(s). Since the only possible intermolecular force of attraction, in this case, are…
Correct answer: Low melting and low boiling points- A. Elimination
- B. Addition
- C. Substitution
- D. Hydrogenation
Explanation: Option A: There is no such evidence of elimination reaction in Benzene since it completely destroys the stability of Benzene.Addition…
Correct answer: Elimination- A. Hydrogenation
- B. Dehydrogenation
- C. Dehydration
- D. None of these options are correct
Explanation: Dehydrogenation is the process by which hydrogen is removed from an organic compound to form a new chemical (e.g., to convert saturated…
Correct answer: Dehydrogenation- A. Benzene reactivity
- B. That benzene has dual character
- C. That benzene has less heat of formation
- D. All of these options are correct
Explanation: Kekule's structure does not explain the extra ordinary stable nature of benzene molecule and its lack of reactivity towards addition…
Correct answer: All of these options are correct- A. Tetrahedral
- B. Hexagonal planar
- C. Hexagonal irregular
- D. Trigonal planar
Explanation: A benzene ring has 6 carbons hence it is a hexagon and it is hexagonal planar and not hexagonal irregular because all the carbons are in…
Correct answer: Hexagonal planar- A. FeBr3
- B. FeCl4-
- C. Cl+
- D. Cl-
Explanation: Electrophiles are species with a positive charge. The only element/molecule with a positive charge is Cl hence, Option C is the correct…
Correct answer: Cl+- A. Hexagonal planar
- B. Square planar
- C. Trigonal planar
- D. Linear
Explanation: Benzene has 6 carbons, hence it is given the name hexagon. All the carbons are in the same planar hence it is called planar.
Correct answer: Hexagonal planar