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 23 of 55
- A. Up to 4.
- B. 5 to 17.
- C. 18 or more.
- D. None of these.
Explanation: Alkanes containing 18 or more carbon atoms are waxy solids. This is due to the increased molecular weight and the closer packing of…
Correct answer: 18 or more.- A. Tin
- B. Nickel
- C. Iron
- D. Sodium
Explanation: The correct option is B because nickel is the catalyst required for the conversion of phenol to cyclohexanol.
Correct answer: Nickel- A. Alkane
- B. Ether
- C. Alkene
- D. Alkyne
Explanation: Option C is correct because alkenes are hydrocarbons that contain at least one double bond between carbon atoms.
Correct answer: Alkene- A. Formaldehyde
- B. Hydrogen
- C. Nitric acid
- D. Sulphuric acid
Explanation: Bakelite, the first synthetic plastic, is produced when phenol reacts with formaldehyde in the presence of a catalyst, making option A…
Correct answer: Formaldehyde- A. Option A: AlCl3
- B. Option B: Alkyl halide
- C. Option C: AlCl3 and alkyl halide
- D. Option D: AlCl3 and FeCl3
Explanation: The introduction of an alkyl group in benzene occurs through Friedel-Crafts alkylation, where the alkyl halide acts as the reagent in the…
Correct answer: Option B: Alkyl halide- A. Cannizzaro's Reaction
- B. Kirchhoff Rule
- C. Aldol Condensation
- D. Markownikov's Rule
Explanation: The addition of unsymmetrical reagents to unsymmetrical alkenes follows Markovnikov's rule.
Correct answer: Markownikov's Rule- A. Alicyclic hydrocarbons
- B. Aromatic hydrocarbons
- C. Acyclic hydrocarbons
- D. Heterocyclic hydrocarbons
Explanation: Aromatic hydrocarbons are the correct answer because they contain benzene rings, which the hydrocarbons shown possess.
Correct answer: Aromatic hydrocarbons- A. CH3C+O
- B. AlCl3
- C. C+H3
- D. CH3COCl
Explanation: When benzene reacts with acetyl chloride (CH3COCI) in the presence of AlCl3, acetophenone is formed.
Correct answer: CH3C+O- A. CH2Br-CH2=CH-CH2
- B. CH2Br-CH2-CH-CH2
- C. CH2Br=CH2-CH=CH2
- D. CH2Br-CH2-CH=CH2
Explanation: 4-Bromobut-1-ene indicates that the alkene is at the 1st position and the bromine is at the 4th position.
Correct answer: CH2Br-CH2-CH=CH2- A. Negative ions
- B. Positive ions
- C. Radicals
- D. Neutral atoms
Explanation: Phenol undergoes ionization by reacting with negative ions like OH- to form the phenoxide ion, which is more stable due to delocalization…
Correct answer: Negative ions- A. conc. H2SO4
- B. dil. HNO3
- C. NaOH with benzene sulphonic acid
- D. Sodium phenoxide with HCI
Explanation: The correct reagent for the formation of o- and p-nitrophenol from phenol at 25°C is dilute nitric acid (dil. HNO3).
Correct answer: dil. HNO3- A. 1,3,6-Trinitrophenol
- B. m-Nitrophenol
- C. Tartaric acid
- D. Picric acid
Explanation: The correct name of the compound shown is 2,4,6-trinitrophenol, with the common name being Picric acid.
Correct answer: Picric acid- A. Option A
- B. Option B
- C. Option C
- D. Option D
Explanation: Option D is the correct answer as it correctly shows the reaction between propanoyl chloride and benzene.
Correct answer: Option D- A. H2SO4
- B. AlCl3
- C. HNO3
- D. HCl
Explanation: In the halogenation of benzene, AlCl3 is used as a catalyst to make the halogen into a strong electrophile.
Correct answer: AlCl3- A. Acidic K2Cr2O7
- B. CuCl2
- C. Acidic NaOH
- D. Alcoholic KOH
Explanation: In β-elimination reactions, alcoholic KOH (potassium hydroxide dissolved in alcohol) is commonly used as the base.
Correct answer: Alcoholic KOH- A. Diffused sunlight
- B. High temperature
- C. U.V light
- D. All of these
Explanation: The correct answer is Option D: All of these. The reason being that in all three cases (diffused sunlight, high temperature, and UV…
Correct answer: All of these- A. FeCl2
- B. FeCl4-
- C. Cl+
- D. Cl2
Explanation: When benzene reacts with a powerful electrophile like Cl+ (chlorine cation), it undergoes electrophilic aromatic substitution reactions…
Correct answer: Cl+- A. H2C = CH2
- B. R - CH = CH - R
- C. R1R2C = CR3R4
- D. R1R2C = CH3R4
Explanation: When R - CH - CH - R alkene is treated with hot concentrated KMnO4 solution, it undergoes oxidative cleavage to produce two moles of…
Correct answer: R - CH = CH - R- A. It is otherwise known as Paraffin
- B. It is an acyclic saturated hydrocarbon
- C. In alkanes, C-C bonds are single
- D. Alkanes have the general formula CnH2n
Explanation: This option is incorrect as the correct formula for alkanes is CnH2n+2, having two additional hydrogen atoms compared to this statement.
Correct answer: Alkanes have the general formula CnH2n- A. Methane
- B. Methene
- C. Ethane
- D. Ethene
Explanation: Methane is the correct answer as it consists of only one carbon atom, which makes it the simplest alkane.
Correct answer: Methane