Practice MCQ For Govt Pharmacist Exam, in this article we will solve, Practice MCQ on the topic, Elimination reactions- E1 and E2 reactions under the subject Pharmaceutical organic chemistry of second semester. Read following article for your reference.
Elimination Reactions- E1 And E2 Reactions » PHARMACAREERS
Which of the following statements is true regarding E1 reactions?
A) E1 reactions occur in a single concerted step.
B) E1 reactions require a strong base.
C) The rate-determining step in E1 reactions is the formation of a carbocation.
D) E1 reactions always yield the anti-Markovnikov product.
What type of mechanism characterizes E2 reactions?
A) Unimolecular
B) Bimolecular
C) Radical
D) Concerted
Which condition favors E2 reactions?
A) Strong base
B) Polar protic solvent
C) Tertiary substrate
D) Heat
In E2 reactions, the hydrogen being removed must be oriented:
A) Syn to the leaving group
B) Anti to the leaving group
C) In a cis arrangement
D) In a trans arrangement
What is the primary role of Zaitsev’s rule in E1 and E2 reactions?
A) Predicting the major product
B) Determining the reaction mechanism
C) Identifying the rate-determining step
D) Calculating activation energy
Which type of alkyl halide is most likely to undergo an E1 reaction?
A) Primary
B) Secondary
C) Tertiary
D) Vinyl
What is the key difference between E1 and E2 reactions?
A) E1 involves a carbocation intermediate, while E2 is concerted.
B) E1 requires a strong base, while E2 requires a weak base.
C) E1 always yields the Markovnikov product, while E2 yields the anti-Markovnikov product.
D) E1 reactions occur at low temperatures, while E2 reactions require heat.
Which alkyl halide is most likely to undergo an E2 reaction?
A) Methyl halide
B) Primary alkyl halide
C) Secondary alkyl halide
D) Tertiary alkyl halide
In which order of reactivity do alkyl halides participate in E1 reactions?
A) Tertiary > Secondary > Primary
B) Primary > Secondary > Tertiary
C) Secondary > Tertiary > Primary
D) Primary = Secondary = Tertiary
Which type of alkyl halide is least likely to undergo an E1 reaction?
A) Methyl halide
B) Primary alkyl halide
C) Secondary alkyl halide
D) Tertiary alkyl halide
What is the key factor influencing E1 reactivity?
A) Base strength
B) Solvent polarity
C) Substrate stability
D) Stereochemistry
Which alkyl halide is most likely to follow Markovnikov’s rule in E1 reactions?
A) Methyl halide
B) Primary alkyl halide
C) Secondary alkyl halide
D) Tertiary alkyl halide
What is the primary purpose of carbocation rearrangements in organic reactions?
A) To increase reaction rate
B) To form stable intermediates
C) To enhance stereochemistry
D) To generate radicals
Which type of rearrangement involves the migration of a hydrogen atom from an adjacent carbon to a carbocation?
A) Hydride shift
B) Alkyl shift
C) Methyl shift
D) Allylic shift
Saytzeff’s rule predicts that in an elimination reaction, the major product will be the alkene with:
A) The fewest alkyl substituents
B) The most alkyl substituents
C) The longest carbon chain
D) The least stable carbocation
Which of the following statements about Saytzeff’s rule is true?
A) It applies only to E1 reactions.
B) It favors the formation of the less substituted alkene.
C) It is based on the stability of the transition state.
D) It guides the orientation of nucleophilic attacks.
What evidence supports the occurrence of carbocation rearrangements?
A) Isotope labeling experiments
B) NMR spectroscopy
C) Mass spectrometry
D) Reaction kinetics studies
Which type of alkyl halide is most likely to undergo carbocation rearrangements during E1 reactions?
A) Primary
B) Secondary
C) Tertiary
D) Vinyl
In E1 reactions, which carbon atom is most likely to bear the positive charge in the carbocation intermediate?
A) The most substituted carbon
B) The least substituted carbon
C) The carbon adjacent to the leaving group
D) The carbon farthest from the leaving group
Which of the following statements is true regarding E1 reactions?
A) E1 reactions occur in a single concerted step.
B) E1 reactions require a strong base.
C) The rate-determining step in E1 reactions is the formation of a carbocation.
D) E1 reactions always yield the anti-Markovnikov product.
What type of mechanism characterizes E2 reactions?
A) Unimolecular
B) Bimolecular
C) Radical
D) Concerted
Which condition favors E2 reactions?
A) Strong base
B) Polar protic solvent
C) Tertiary substrate
D) Heat
In E2 reactions, the hydrogen being removed must be oriented:
A) Syn to the leaving group
B) Anti to the leaving group
C) In a cis arrangement
D) In a trans arrangement
What is the key difference between E1 and E2 reactions?
A) E1 involves a carbocation intermediate, while E2 is concerted.
B) E1 requires a strong base, while E2 requires a weak base.
C) E1 always yields the Markovnikov product, while E2 yields the anti-Markovnikov product.
D) E1 reactions occur at low temperatures, while E2 reactions require heat.
Which type of alkyl halide is most likely to undergo an E1 reaction?
A) Primary
B) Secondary
C) Tertiary
D) Vinyl
What is the primary role of Zaitsev’s rule in E1 and E2 reactions?
A) Predicting the major product
B) Determining the reaction mechanism
C) Identifying the rate-determining step
D) Calculating activation energy
What is the primary purpose of ozonolysis in organic chemistry?
A) To form alcohols
B) To cleave double bonds using ozone
C) To generate radicals
D) To synthesize alkynes
Which functional groups are commonly formed during ozonolysis of alkenes?
A) Aldehydes, ketones, or carboxylic acids
B) Alcohols and ethers
C) Amines and amides
D) Alkenes and alkynes
What initiates electrophilic addition reactions to alkenes?
A) Electrons from the π-bond attack an electrophile
B) Electrons from the σ-bond attack a nucleophile
C) Electrons from the π-bond attack a nucleophile
D) Electrons from the σ-bond attack an electrophile
According to Markovnikov’s rule, where does hydrogen tend to add in electrophilic addition reactions?
A) To the more substituted carbon
B) To the less substituted carbon
C) To the carbon adjacent to the leaving group
D) To the carbon farthest from the leaving group
Which type of alkene addition reaction can lead to anti-Markovnikov products?
A) Electrophilic addition
B) Radical addition
C) Nucleophilic addition
D) Acid-catalyzed addition
What does Markovnikov’s rule predict in the addition of a protic acid (HY) to an unsymmetrical alkene?
A) Hydrogen adds to the more substituted carbon.
B) Hydrogen adds to the less substituted carbon.
C) Hydrogen adds randomly to either carbon.
D) Hydrogen adds to the carbon adjacent to the leaving group.
Which product is considered the Markovnikov product in an addition reaction?
A) The one with the most hydrogen atoms
B) The one with the fewest hydrogen atoms
C) The one with the longest carbon chain
D) The one with the most substituents
Free Radical Addition Reactions of Alkenes:
What initiates free radical addition reactions to alkenes?
A) Electrons from the π-bond attack an electrophile
B) Electrons from the σ-bond attack a nucleophile
C) Formation of alkoxy radicals
D) Formation of carbocations
Which type of alkene addition reaction can lead to anti-Markovnikov products?
A) Electrophilic addition
B) Radical addition
C) Nucleophilic addition
D) Acid-catalyzed addition
What does the anti-Markovnikov rule describe?
A) The addition of hydrogen to the more substituted carbon
B) The addition of hydrogen to the less substituted carbon
C) The formation of the most stable carbocation
D) The preference for syn-addition in electrophilic reactions
Which type of alkene addition reaction can lead to anti-Markovnikov products when peroxides are involved?
A) Electrophilic addition
B) Radical addition
C) Nucleophilic addition
D) Acid-catalyzed addition
For more regular updates you can visit our social media accounts,
Instagram: Follow us
Facebook: Follow us
WhatsApp: Join us
Telegram: Join us