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 31 of 55
- A. Isopropyl chloride
- B. Chlorobenzene
- C. Bromobenzene
- D. Chloroethene
Explanation: In the Friedel-Crafts reaction, an electrophile attacks an aromatic ring to substitute a hydrogen atom.
Correct answer: Isopropyl chloride- A. SO3
- B. NO2+
- C. NO3
- D. NO+
Explanation: In the electrophilic substitution reaction of benzene using oleum and concentrated sulfuric acid, the electrophile is the sulfur trioxide…
Correct answer: SO3- A. NO2
- B. NHCOCH3
- C. CN
- D. NH2
Explanation: The most activating group in electrophilic aromatic substitution is NH2.
Correct answer: NH2- A. AlCl3
- B. CO+
- C. Cl+
- D. R-CO+
Explanation: In the acylation of benzene, the correct electrophile is R-CO+. This is formed when an acyl chloride reacts with a Friedel-Crafts catalyst…
Correct answer: R-CO+- A. Benzoic acid
- B. Toluene
- C. Aniline
- D. Nitrobenzene
Explanation: The correct answer is Toluene. Friedel-Crafts alkylation requires an electrophile to attack an aromatic ring, which must be electron-rich.
Correct answer: Toluene- A. MgCl2
- B. AlCl3
- C. NaF
- D. CaCl2
Explanation: Friedel-Crafts alkylation is an electrophilic aromatic substitution reaction that utilizes an alkyl halide and a Lewis acid, typically…
Correct answer: AlCl3- A. -OH
- B. -OCH3
- C. -Cl
- D. -CH3
Explanation: The correct answer is -OH because it is the strongest ortho, para directing group among the options provided.
Correct answer: -OH- A. COOH
- B. CN
- C. COCH3
- D. NHCOCH3
Explanation: The amide group (NHCOCH3) is an ortho/para directing group. This means that it will direct the incoming electrophile to the ortho and para…
Correct answer: NHCOCH3- A. Same physical properties and different chemical properties
- B. Different physical properties and same chemical properties
- C. Same physical and chemical properties
- D. Different physical and chemical properties
Explanation: The main difference between ortho and para-hydrogen is the spin of their nuclei.
Correct answer: Different physical properties and same chemical properties- A. Ortho position
- B. Para position
- C. Meta position
- D. Both Ortho and para position
Explanation: Deactivated substituent groups withdraw electrons from the aromatic ring, reducing its reactivity towards electrophiles.
Correct answer: Meta position- A. - NO2
- B. - NH2
- C. - OH
- D. F
Explanation: The nitro group (NO2) is electron-withdrawing due to the high electronegativity of nitrogen, which pulls electrons away from the benzene…
Correct answer: - NO2- A. - NH2
- B. - Br
- C. -COOH
- D. - OH
Explanation: The correct answer is -COOH. The carboxyl group is an electron withdrawing group, making it a meta directing group on a benzene ring.
Correct answer: -COOH- A. NO2
- B. -NO
- C. - SO3
- D. - SO2ME
- E. Non of these
Explanation: The correct answer is option A: NO2. It is ortho para in electrophilic substitution and ortho para in nucleophilic substitution.
Correct answer: Non of these- A. Benzene
- B. Chlorobenzene
- C. Nitrobenzene
- D. Toluene
Explanation: The sulphonation reaction of aromatic compounds involves the electrophilic substitution of a hydrogen atom on the aromatic ring with a…
Correct answer: Toluene- A. -NHCOCH3
- B. -NO2
- C. -CN
- D. -CHO
Explanation: The correct answer is -NHCOCH3 because it can donate electrons through resonance to stabilize positive charge, making it ortho para…
Correct answer: -NHCOCH3- A. Ortho position
- B. Para position
- C. Both Ortho and para position
- D. Mata position
Explanation: Activating groups are electron-donating groups that make the ring more reactive.
Correct answer: Both Ortho and para position- A. 500 dm3
- B. 1000 dm3
- C. 1500 dm3
- D. 2000 dm3
Explanation: 1 mole of ethene reacts with 3 moles of O2 to burn completely. C2H4 + 3O2 → 2CO2 + 2H2O So, 500dm^3 will react with 1500 dm^3 (500 × 3…
Correct answer: 1500 dm3- A. Friedel Craft's acylation
- B. Friedel Craft's alkylation
- C. Halogenation of benzene
- D. Benzene sulphonic acid
Explanation: The reaction of benzene will alkyl chloride in presence of AlCl3 as Lewis base is known as Friedel-Crafts alkylation.Hence, option B is…
Correct answer: Friedel Craft's alkylation- A. m- nitrobenzoic acid
- B. o- nitrobenzoic acid and p- nitrobenzoic acid
- C. m-nitrotoluene
- D. o-nitrotoluene and p-nitrotoluene
Explanation: When benzene is subjected to alkylation, the product formed will be alkyl benzene.
Correct answer: o- nitrobenzoic acid and p- nitrobenzoic acid- A. Chlore methane
- B. dichloro methane
- C. trichloro methane
- D. tetrachloromethane
Explanation: The molecular formula of chloroform is CHCl3. Since, three chloride atoms are attached to carbon atom, so IUPAC name of chloroform will be…
Correct answer: trichloro methane