Free Alkenes MCQs with Answers
89 Alkenes MCQs from Chemistry, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Alkenes are unsaturated hydrocarbons containing a carbon-carbon double bond with sigma and pi components and restricted rotation. Their reactions include electrophilic addition of hydrogen, halogens, hydrogen halides and water, with Markovnikov orientation, oxidation, combustion and polymerisation, while their preparation commonly involves elimination from alkyl halides or alcohols.
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89 questions · page 4 of 5
- A. Dehydration
- B. Ozonolysis
- C. Markovnikov's addition
- D. Oxidation with KMnO4
Explanation: The types of products obtained for ozonolysis can be used to determine the position of the double bond in compounds.
Correct answer: Ozonolysis- 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 bond66. 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. Carbinol
- B. Methanol
- C. Ethanol
- D. Glycol
Explanation: Ethylene we know is an alkene They mentioned ethylene is going to react with water, it means it is hydration of an alkene And we know…
Correct answer: Ethanol- A. Water
- B. Ethyle alcohol
- C. Ammonia
- D. Carbon tetrachloride
Explanation: We also know alkenes are non-polar, with negligible electronegativity difference between carbon and hydrogen and no difference between…
Correct answer: Carbon tetrachloride- A. Propylene
- B. Propane
- C. Propene
- D. Propanol
Explanation: To solve such questions, the catalyst tells the whole answer, In the first step alcohol is reacted with PCl3 to form a product A Alcohol…
Correct answer: Propene- A. Water
- B. Ethyle alcohol
- C. Ammonia
- D. Carbon tetrachloride
Explanation: Alkenes are only soluble in nonpolar solvents.
Correct answer: Carbon tetrachloride- A. Nucleophiles
- B. Electrophiles
- C. Carbon ions
- D. Carbonium ions
Explanation: Alkenes undergo electrophilic substitution reaction. Hence in the reaction between ethene and HCl, hydrogen acts as an electrophile and is…
Correct answer: Electrophiles- A. Rropylene
- B. Propane
- C. Propene
- D. Propanol
Explanation: Alcohol reacts with PCl3 to form Alkyl Halides by nucleophilic substitution reaction forming akene (reaction shown below):
Correct answer: Propene- A. Water
- B. Ethyl alcohol
- C. Ammonia
- D. Carbon tetrachloride
Explanation: CCl4 is non polar so as ethene is... They dissolve in each other perfectly because of same nature
Correct answer: Carbon tetrachloride- A. water
- B. ethyl alcohol
- C. ammonia
- D. carbon tetrachloride
Explanation: CCl4 is non polar so alkene dissolves in it best LIKE DISSOLVES LIKE. As, alkenes is non polar so it will dissolve in non polar solvent
Correct answer: carbon tetrachloride- A. Less susceptible to oxidation
- B. More susceptible to oxidation
- C. Equally susceptible to oxidation
- D. All of these
Explanation: A carbon-carbon double bond represents unsaturation, while a single carbon-carbon bond represents saturated hydrocarbons, alkanes that are…
Correct answer: More susceptible to oxidation- A. Addition of bromine water
- B. Addition of HI
- C. Oxidation with ozone
- D. All of the above
Explanation: Ozonolysis, i.e., oxidation with ozone, is the method used to point out the position of a double bond in an organic compound.
Correct answer: Oxidation with ozone- A. 1-pentene
- B. 2-pentene
- C. 2-Methyl-1-butene
- D. 3-Methyl-1-butene
Explanation: The reaction of alkenes with bromine proceeds through the formation of a carbocation intermediate.
Correct answer: 3-Methyl-1-butene- A. 4- Methyl-1-Pentene
- B. 2- Methyl-3- Pentene
- C. 2- Methyl-2- Pentene
- D. 4,4-Dirnethyl-2-Pentene
Explanation: According to the IUPAC system of naming compounds, the methyl group is the substituent that will have secondary importance because the…
Correct answer: 4- Methyl-1-Pentene- A. C5 H22
- B. C5 H10
- C. C5 H8
- D. C4 H10
Explanation: The general formula for alkenes is CnH2n, where n=5 is the formula for alkene C5H10
Correct answer: C5 H10- A. C2H4 > C2H2 > C6H6
- B. C6H6 > C2H4 > C2H2
- C. C2H4 > C2H4 > C6H6
- D. C2H2 > C6H6 > C2H4
Explanation: In electrophilic addition reactions, the reactivity order is C2H4 (alkene) > C2H2 (alkyne) > C6H6 (benzene).
Correct answer: C2H4 > C2H2 > C6H6