Do the numbers 1 and 2 in E1 and E2 reactions relate to the number of steps in the elimination reaction's mechanism?

Answer 1

No, the numbers do not refer to the number of steps in the mechanism.

They refer to the molecularity of the reaction, that is, to the number of particles that are involved in the rate determining step.

E1 Elimination

In an E1 elimination, the leaving group departs first to form an intermediate carbocation. Then a base attacks a β hydrogen in the carbocation to form the alkene.

The first step is the rate determining step. Since it involves only the substrate (and not the base), it is called a unimolecular reaction.

The "uni" means "one". That's where the 1 in the name E1 comes from.

Note that an E1 reaction is a two-step reaction.

E2 Elimination

In an E2 elimination, the leaving group departs at the same time as the base attacks.

There is a single transition state that consists of both the base and the substrate.

Since the rate determining step involves two particles, this is a bimolecular reaction.

The "bi" means "two". That's where the 2 in the name E2 comes from.

Note that an E2 reaction is a one-step reaction.

Here's a video that compares E1 and E2 eliminations.

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Answer 2

Yes, the numbers 1 and 2 in E1 and E2 reactions refer to the number of steps in the elimination reaction's mechanism. E1 reactions proceed through a unimolecular elimination mechanism, involving one step. E2 reactions involve a bimolecular elimination mechanism, with two species participating in the rate-determining step.

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Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

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