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 51 of 55
- A. Finely divided nickel
- B. Finely divided iron
- C. Vanadium pentaoxide
- D. Copper
Explanation: The hydrogenation of unsaturated oils is done under high temperature and pressure with nickel used as a catalyst.
Correct answer: Finely divided nickel- A. 3, 3-dimethyl-3-hexene
- B. 3, 4-dimethyl-3-hexene
- C. 3-hexene
- D. 2,3-dimethyl-1-hexene
Explanation: KEY POINTS the structure is a six-carbon Hydrocarbon containing two methyl substitutions and a double bond Metal substitution are present…
Correct answer: 3, 4-dimethyl-3-hexene- A. Reduction
- B. Oxidation
- C. Hydroxylation
- D. Hydration
Explanation: In a hydration reaction, a water molecule is added to the unsaturated reactants to form an alcohol.
Correct answer: Hydration- A. Detection of ketones
- B. Detection of double bond
- C. Identification of Primary and Secondary alcohols
- D. Detection of Aldehydes
Explanation: The electrophilic addition of bromine to Alkenes in the cold with pure liquid bromine, or with a solution of bromine in an organic solvent…
Correct answer: Detection of double bond1005. Alkenes undergo:
- A. Electrophilic Addition
- B. Electrophilic substitution
- C. Nucleophilic substitution
- D. Nucleophilic addition
Explanation: Alkenes have a pi bond between carbon atoms, which is an area of electron density i.e.
Correct answer: Electrophilic Addition- A. NO2-
- B. HNO2
- C. NO3-
- D. NO2+
Explanation: Explanation:During the nitration of benzene which is an electrophilic substitution reaction, the active nitrating agent is NO2+.
Correct answer: NO2+- A. Alkyl group
- B. Phenyl group
- C. Benzyl group
- D. Methyl group
Explanation: A is incorrect as alkyl group is formed when one hydrogen is removed from an alkane chain;not a benzene ring.B is correct as when one…
Correct answer: Phenyl group- A. Conc. HNO3 and conc. HCl
- B. Conc. HNO3 and conc. Acetic acid
- C. Conc. HNO3 and H3PO4
- D. Conc. HNO3 and conc. H2SO4
Explanation: A is incorrect as these reactants are not used in nitration.B is incorrect as these reactants are not used in nitration.C is incorrect as…
Correct answer: Conc. HNO3 and conc. H2SO4- A. Acetyl chloride
- B. Acetic acid
- C. Ethyl benzene
- D. Ethanoic acid
Explanation: The benzene reacts with acetyl chloride in presence of anhydrous aluminum chloride to form acetophenone.
Correct answer: Acetyl chloride- A. Nitration
- B. Ammonolysis
- C. Sulphonation
- D. Reduction of benzene
Explanation: Nitration reactions are the addition of a nitro group into an organic compound.
Correct answer: Nitration- A. Acylation
- B. Carbonyl reduction
- C. Alkylation
- D. Formylation
Explanation: The introduction of an RC(O)+ group (also called an acyl group) in benzene is called acylation.
Correct answer: Acylation- A. Option A
- B. Option B
- C. Option C
- D. Option D
Explanation: We are asked to describe the possible product of bromination. From the question, we can possibly conclude that the OH group is already…
Correct answer: Option C- A. Option A
- B. Option B
- C. Option C
- D. Option D
Explanation: This set of reaction is known as Friedal Craft Acylation and in this, CH3CH3COCl i.e propanoyl chloride reacts with benzene and the…
Correct answer: Option D- A. ii, iii, iv
- B. ii, iii
- C. i, iv
- D. i, ii, iv
Explanation: The 3 5 directing groups or Meta directing groups are as follows:Aldehyde (-CHO), Ketone (-CO-), Ester (-RCOOR'), Carboxyl Group (-COOH)…
Correct answer: ii, iii- A. CH3CO+
- B. AlCl3
- C. CH3+
- D. CH3COCl
Explanation: CH3COCl reacts with AlCl3 to form ----> AlCl4- and CH3CO+CH3CO+ has a positive charge thus it is an electrophile and attracted to…
Correct answer: CH3CO+- A. Electrophilic addition
- B. Electrophilic substitution
- C. Nucleophilic substitution
- D. Nucleophilic addition
Explanation: Benzene has an extended delocalised pi system above and below the ring which makes it highly attracted to electron-deficient species…
Correct answer: Electrophilic substitution- A. Br+
- B. FeCl4+
- C. Fe2+
- D. Fe3+
Explanation: Benzene reacts with bromine in an electrophilic substitution reaction, but only in the presence of a catalyst to yield bromobenzene.
Correct answer: Br+- A. Benzoic acid
- B. Methyl benzene
- C. Benzaldehyde
- D. Nitrobenzene
Explanation: Activating groups increase the reactivity of electrophilic substitutions, whereas deactivating groups decrease it.Activating groups are…
Correct answer: Methyl benzene- A. Cl-
- B. Cl+
- C. Cl2
- D. Cl0
Explanation: A free radical is an atom, molecule or ion that has an unpaired electron.
Correct answer: Cl0- A. Cracking
- B. Reforming
- C. Polymerisation
- D. Condensation
Explanation: As we see, just straight-chain alkane is converted into branched-chain alkane, nothing else and this conversion is called Reforming.
Correct answer: Reforming