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 21 of 23
- A. BH3
- B. NH3
- C. -NH2
- D. -OH
Explanation: A nucleophile is a chemical species that donates a lone pair of electrons to form a chemical bond to another electron deficient species.
Correct answer: BH3- A. Propene
- B. Propan-1-ol
- C. Propan-2-ol
- D. Potassium Propoxide
Explanation: a) Propene:When 2-bromopropane is heated with concentrated alcoholic potassium hydroxide (KOH), it undergoes an elimination reaction known…
Correct answer: Propene- A. C2H4
- B. C2H5OH
- C. C2H4ClOH
- D. C2H6
Explanation: A is correct option because When ethyl chloride is reacted with alcoholic KOH, ethylene is formed.
Correct answer: C2H4- A. Combustion reaction
- B. Oxidation
- C. Elimination reaction
- D. Addition reaction
Explanation: Tertiary alcohols undergo dehydration/elimination reaction to form alkenes under specific conditions i.e., heat + concentrated sulphuric…
Correct answer: Elimination reaction- A. Substitution reaction
- B. Elimination reaction
- C. Addition reaction
- D. Replacement reaction
Explanation: In elimination reactions, molecules are removed from compounds without the addition of subsequent molecules.
Correct answer: Elimination reaction- A. 1-Ethyl-3, 4 - dimethylcycloheptane
- B. 2-Ethyl-4, 5-dimethylcyclohexane
- C. 1-Ethyl - 4, 4-dimethylcyclohexane
- D. 4-Ethyl-1, 2 - dimethylcyclohexane
Explanation: Apply rules of nomenclature. The adjacent methyl groups will be preffered first because they are closer compared to ethyl and methyl groups.
Correct answer: 4-Ethyl-1, 2 - dimethylcyclohexane- A. Ethyl chloride
- B. Ethene chlorine
- C. Chiaro ethane
- D. Vinyl chloride
Explanation: The compound shown is Vinyl Chloride, which is an organochloride with the formula H₂C=CHCl.
Correct answer: Vinyl chloride- A. CH3Cl
- B. CH2Cl2
- C. CHCl3
- D. CH2Cl
Explanation: Chloroform or trichloromethane is an organic compound which has a molecular formula CHCl3. The answer is C.
Correct answer: CHCl3- A. Primary and secondary
- B. Secondary and tertiary
- C. Primary and tertiary
- D. Primary, secondary and tertiary
Explanation: a) Primary and secondary:This option suggests that both primary and secondary halogenoalkanes can react with alkali by an SN2…
Correct answer: Primary and secondary- A. BF3
- B. SO3
- C. AlCl3
- D. CN
Explanation: Nucleophiles are elements/compounds containing extra pairs of electrons.
Correct answer: CN- A. A carbocation
- B. A free radical
- C. A carbanion
- D. An intermediate complex
Explanation: When nucleophilic substitution takes place bond between C and X dissociates.
Correct answer: A carbocation- A. Substrate
- B. Nucleophile
- C. Both Options A and B are correct
- D. None of these options are correct
Explanation: In SN2 reactions, the rate of the reaction is directly proportional to the concentration of the nucleophile and the concentration of the…
Correct answer: Both Options A and B are correct- A. From the opposite side of the leaving group
- B. From the front of the leaving group
- C. From both sides
- D. None of these options are correct
Explanation: The correct answer is: From both sides. The nucleophile can attack the carbocation from either the front or the back side during an SN1…
Correct answer: From both sides- A. Water
- B. Benzene
- C. Carbon Tetrachloride
- D. Carbon disulphide
Explanation: SN1 reactions are favored by Polar prototic Solvents. These are polar solvents that are able to show hydrogen bonding.
Correct answer: Water- A. A carbocation
- B. A free radical
- C. A carbanion
- D. An intermediate complex
Explanation: In the first step of an SN1 reaction, the halide atom of the alkyl halide is removed, and the carbon atom becomes sp2 hybridized.
Correct answer: A carbocation- A. Sp2 to sp3
- B. Sp to sp2
- C. Sp3 to sp2
- D. Sp to sp3
Explanation: Normally, a carbon atom is sp3 hybridized. In the transition state of the SN2 mechanism, the carbon atom is sp2 hybridized due to its…
Correct answer: Sp3 to sp2- A. Electrophile
- B. Base
- C. Leaving group
- D. Acid
Explanation: Bases are proton acceptors and OH- is a base as it eliminates H+ (proton) from the reactant and forms a water molecule.
Correct answer: Base- A. Strong bases causes substitution in preference to elimination
- B. Role of leaving groups in elimination is simitar to substitution
- C. Substitution is favored more than elimination by decreasing solvent polarity
- D. Decrease in temperature will favor elimination more than substitution
Explanation: This statement is correct. In both substitution and elimination reactions, the effectiveness of the leaving group plays a crucial role; a…
Correct answer: Role of leaving groups in elimination is simitar to substitution- A. Dry Ether
- B. Alcohol
- C. CS2
- D. CCl4
Explanation: Explanation:Grignard reagents are prepared by the reaction of magnesium metal with alkyl halides in the presence of dry ether.
Correct answer: Dry Ether- A. 1-Bromo-1-chloro-2, 2, 2-trifluoroethane
- B. 2-Bromo-2-chloro-1, 1, 1-trifluoroethane
- C. 1, 1, 1-Trifluoro-2-bromo-2-chloroethane
- D. 2-Chloro-2-bromo-1, 1, 1-trifluoroethane
Explanation: 2-Bromo-2-chloro-1,1,1- trifluoroethane is the IUPAC name for halothanes that are used in hospitals as an anaesthetic.
Correct answer: 2-Bromo-2-chloro-1, 1, 1-trifluoroethane