Free Alkyl Halides MCQs with Answers
458 Alkyl Halides MCQs from Chemistry, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Alkyl halides are named and related to their carbon-halogen structure, polarity and reactivity. The key reactions are nucleophilic substitution by SN1 and SN2 mechanisms and elimination by E1 and E2 mechanisms, including how substrate structure, nucleophile, base, solvent and temperature influence substitution versus elimination.
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Read the Alkyl Halides notesFree MDCAT chapter notes with key terms458 questions · page 20 of 23
- A. Substrate only
- B. Nucleophile
- C. Both A and B
- D. None of these
Explanation: Option C is correct since we know that an SN2 mechanism is a one-step process in which the nucleophile attacks the substrate and the…
Correct answer: Both A and B- A. Electrophilic carbon
- B. Nucleophilic carbon
- C. Beta-hydrogen
- D. None of these
Explanation: This is the elimination reaction. In step 2 , which is the removal of β-hydrogen, base attacks β-hydrogen to form alkene.
Correct answer: Beta-hydrogen383. SN2 reactions are _?
- A. Nucleophilic unimolecular addition reactions
- B. Nucleophilic bimolecular substituition reactions
- C. Nucleophilic bimolecular addition reactions
- D. Nucleophilic unimolecular substitution reactions
Explanation: SN2 is a nucleophilic bimolecular substitution reaction. Hence, B is the correct option.
Correct answer: Nucleophilic bimolecular substituition reactions- A. Iodine reacts slowly
- B. Iodine reacts reversibly
- C. HI formed reduces alkyl iodide again to starting material
- D. All of these options are correct
Explanation: Alkyl iodides cannot be prepared directly by the halogenation of alkanes because iodine reacts slowly and reversibly as well as the…
Correct answer: All of these options are correct- A. NH2ˉ
- B. H2O
- C. BF3
- D. CH3ˉ
Explanation: Nucleophiles are electron donors and they usually have a negative charge.
Correct answer: BF3- A. R - Cl > R - Br > R - F > R - 1
- B. R -I > R - Br > R - CI > R - F
- C. R - I > R - CI > R - Br > R - F
- D. None of these
Explanation: The correct order of reactivity for alkyl halides in nucleophilic substitution reactions is generally R - I > R - Br > R - Cl > R - F…
Correct answer: R -I > R - Br > R - CI > R - F- A. Deactivate the ring; meta directing
- B. Activate the ring; ortho-para directing
- C. Deactivate the ring; ortho-para directing
- D. Activate the ring; meta directing
Explanation: decreasesAmmonia is a meta-directing group. It is also a deactivating group.
Correct answer: Deactivate the ring; meta directing- A. 1st order kinetics
- B. 2nd order kinetics
- C. Zero order kinetics
- D. None of these
Explanation: Option B is correct.Elimination bimolecular reactions involve second-order kinetics.
Correct answer: 2nd order kinetics- A. They have an electrophilic carbon
- B. They have an electrophilic carbon and a good leaving group
- C. They have an electrophilic carbon and a bad leaving group
- D. They have a nucleophilic carbon and a good leaving group
Explanation: Option B is correct.Alkyl halides are considered to be very reactive compounds towards nucleophiles because they have an electrophilic…
Correct answer: They have an electrophilic carbon and a good leaving group- A. The presence of halogen atom
- B. The polarity of C - Mg bond
- C. The presence of Mg atom
- D. The polarity of C - X bond
Explanation: Grignard reagents are reactive due to the polarity of the carbon-magnesium (C-Mg) bond.
Correct answer: The polarity of C - Mg bond391. SN2 reactions are _?
- A. Two step reactions
- B. Multistep reactions
- C. Single step reactions
- D. None of these
Explanation: SN2 reactions are single step reactions. The correct answer is C. In SN2 (substitution nucleophilic bimolecular) reactions, the…
Correct answer: Single step reactions- A. E1, S2
- B. E2, S1
- C. E2, S2
- D. E1, S1
Explanation: The correct answer is d) E1, S1. The first step of both E1 and S1 reactions involves the formation of a carbocation intermediate.
Correct answer: E1, S1- A. From the side of leaving group
- B. Opposite to the leaving group
- C. In front of the leaving group
- D. Below the leaving group
Explanation: In an SN2 (substitution nucleophilic bimolecular) reaction, the nucleophile attacks the electrophilic carbon from the opposite side of the…
Correct answer: Opposite to the leaving group- A. Ca in anhydrous ether
- B. Mg in dry ether
- C. Mg in moist ether
- D. Ca in dry ether
Explanation: Grignard reagents are produced by the reaction of alkyl halides with magnesium (Mg) in dry ether. The correct option is B.
Correct answer: Mg in dry ether395. SN1 reaction is a _?
- A. Multistep reaction
- B. Two step reaction
- C. Concerted reaction
- D. Three step reaction
Explanation: SN1 reactions are two-step reactions. The correct answer is B. In the first step, the leaving group departs, forming a carbocation…
Correct answer: Two step reaction- A. Electrophilic carbon
- B. Nucleophilic carbon
- C. β-hydrogen
- D. None of these
Explanation: In a reaction involving both alkyl halide and a base, the base will attack on β-hydrogen.
Correct answer: β-hydrogen- A. From opposite side of the leaving group
- B. From front of the leaving group
- C. From both sides
- D. None of these
Explanation: Option c is correct. In SN1 reactions, since the nucleophile attacks the planar carbocation intermediate, it can indeed approach from…
Correct answer: From both sides- A. Electrophile
- B. Lewis acid
- C. Electron deficient species
- D. Bear all properties
Explanation: The function of AlCl3(anhydrous), in the Friedel-Craft reaction, is to produce electrophile, which later adds to the benzene nucleus.
Correct answer: Lewis acid- A. My brother, you and myself did it
- B. You, my brother and myself did it.
- C. My brother, you and me did it.
- D. You, my brother, and I did it.
Explanation: The correct sentence is (D) "You, my brother, and I did it." It uses the correct subject pronouns "you" and "I," and correctly places "my…
Correct answer: You, my brother, and I did it.- A. Each of the chemical antiseptics was more harmfully to the leucocytes than to the germs.
- B. Each of the chemical antiseptics was more harmful to the leucocytes then to the germs.
- C. Each of the chemical antiseptics were more harmful to the leucocytes than to the germs.
- D. Each of the chemical antiseptics was more harmful to the leucocytes than to the germs.
Explanation: Each of the chemical antiseptics was more harmful to the leucocytes than to the germs.
Correct answer: Each of the chemical antiseptics was more harmful to the leucocytes than to the germs.