Elimination and Substitution Reactions

In this episode of Crash Course Organic Chemistry, Deboki Chakravarti uses an adventure game analogy to explain organic chemistry concepts. The video covers different substrate classes—methyl, primary, secondary, and tertiary—and their reactions, including SN1, SN2, E1, and E2 mechanisms. It discusses how nucleophiles, likened to magic potions, interact with substrates under various conditions. The episode also provides problem-solving examples to reinforce learning and concludes with a preview of the next topic: alcohols, ethers, and epoxides.

In the adventure game analogy, what role do nucleophiles play?

• They are the main characters.

• They are the final bosses.

• They are the obstacles.

• They are the magic potions.

Which type of substrate is most likely to undergo only SN2 reactions?

• Primary substrates

• Secondary substrates

• Tertiary substrates

• Methyl substrates

What is a key characteristic of primary substrates that affects their reaction pathways?

• They have stable carbocations.

• They have no beta hydrogens.

• They have a bulky structure.

• They have a leaving group at the end of the chain.

What type of reaction is favored when a secondary substrate encounters a strong, bulky base?

• E1

• SN2

• E2

• SN1

In SN1 reactions involving secondary substrates, what can happen to the stereochemistry?

• It forms a single diastereomer.

• It becomes enantiomerically pure.

• It becomes racemic.

• It remains unchanged.

What is the main reason tertiary substrates do not undergo SN2 reactions?

• They form stable carbocations.

• They have no leaving group.

• They lack beta hydrogens.

• They have too much steric hindrance.

Which reaction is favored for tertiary substrates in the presence of a strong base?

• SN2

• E1

• SN1

• E2

According to Zaitsev’s rule, what is the major product in elimination reactions?

• The alkene with the lowest energy

• The least substituted alkene

• The most substituted alkene

• The alkene with the highest energy

What is the effect of heat on elimination reactions?

• It slows them down.

• It favors them.

• It has no effect.

• It converts them to substitution reactions.

What is a hydride shift in the context of carbocation rearrangements?

• A shift of a hydrogen atom to form a more stable carbocation

• A shift of a carbon atom to form a less stable carbocation

• A shift of a hydrogen atom to form a less stable carbocation

• A shift of a carbon atom to form a more stable carbocation