Introduction to the Alpha Carbon in Organic Chemistry

What is formed when the alpha hydrogen of an organic compound is removed?

• A carbocation

• An enolate ion

• A free radical

• A carbanion

How does resonance stabilization affect the acidity of the alpha hydrogen in carbonyl compounds?

• It decreases the acidity because the negative charge is delocalized

• It has no effect on the acidity

• It increases the acidity because the negative charge is delocalized

• It increases the acidity by increasing the positive charge

Which of the following best describes nucleophilic substitution reactions involving alpha carbons?

• The alpha carbon acts as a nucleophile

• The alpha carbon does not participate in these reactions

• The alpha carbon acts as an electrophile

• The reaction only occurs in the presence of a strong base

What is keto-enol tautomerism?

• A process where a ketone is converted into an ester

• A process where a ketone and its enol form are in equilibrium

• A reaction that converts alcohols into ketones

• A reaction where a ketone is permanently converted into an enol

Why is the enolate ion a good nucleophile?

• Because it has a positive charge

• Because it is resonance stabilized

• Because it has a high electronegativity

• Because it is a large ion

In keto-enol tautomerism, what role does the acid or base catalyst play?

• It donates a proton to the alpha carbon

• It helps to stabilize the enolate ion

• It facilitates the removal or addition of a proton at the alpha carbon

• It has no role in the tautomerism process

Which of the following best describes the alpha carbon in a molecule?

• The carbon atom adjacent to a carbonyl group or functional group.

• The carbon atom bonded to the functional group in an organic compound.

• The first carbon atom in a chain of carbon atoms.

• The carbon atom directly bonded to a heteroatom in a molecule.