Question

A ____________ alkene is more stable than a ____________ alkene because they have fewer steric interactions. In an elimination reaction, a geometry where the β hydrogen and the leaving group are on opposite sides of the molecule is called ____________ periplanar. In an ____________ mechanism, a nucleophile attacks the carbocation, forming a substitution product, while in an ____________ mechanism, a base removes a β hydrogen from the carbocation, forming a new π-bond. CH3CH2Br and NaOH react by an ____________ mechanism. Stronger bases, like hydroxide, favor ____________ reactions, whereas weaker bases, like water favor, ____________ reactions. Disubstituted alkenes always have the possibility to exist as two different ____________ . ____________ reactions are regioselective, favoring formation of the more substituted and more stable alkene

Answer 1

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Step-by-step explanation:

A trans alkene is more stable than a cis alkene because they have fewer steric interactions.

⇒ In a cis alkene there is steric hindrance, because the methyl groups are on the same side of the double bond.

Because of this steric crowding, there are van der Waals repulsive forces between the electron clouds of the groups.

This decreases the stability of the cis alkene.

In an elimination reaction, a geometry where the β hydrogen and the leaving group are on opposite sides of the molecule is called anti periplanar.

⇒ 'Anti’ refers to the two functional groups lying on opposite sides of the plane of the bond

In an SN1 mechanism, a nucleophile attacks the carbocation, forming a substitution product,

⇒ The SN1 reaction is a substitution reaction, and means "nucleophilic substitution".The "1" says that the rate-determining step is unimolecular. Thus, the rate equation is often shown as having first-order dependence on electrophile and zero-order dependence on nucleophile.

while in an E1 mechanism, a base removes a β hydrogen from the carbocation, forming a new π-bond.

⇒ E1 indicates a elimination, unimolecular reaction

This implies that the rate determining step of the mechanism depends on the decomposition of a single molecular species.

.This is a classic elimination reaction – forming a new C–C(π) bond, and breaking a C–H and C–leaving group bond.

CH3CH2Br and NaOH react by an SN2 mechanism.

⇒ It's a type of reaction mechanism that is common in organic chemistry, where one bond is broken and one bond is formed, synchronously, (in one step.)

Stronger bases, like hydroxide, favor E2 reactions, whereas weaker bases, like water favor, E1 reactions

Disubstituted alkenes always have the possibility to exist as two different Diastereomer.

Diastereomer are stereoisomers that are not mirror images of one another and are non-superimposable on one another. They exist (always) in 2 forms.

Elimination reactions are regioselective, favoring formation of the more substituted and more stable alkene.