OAT Organic Chemistry 4

Question 1

Which reagent is used to reduce a carboxylic acid to a primary alcohol?

Accepted Answer

LiAlH4

Answer

LiAlH4 is a strong enough hydride donor to reduce carboxylic acids all the way to primary alcohols; NaBH4 cannot.

Question 2

What is the IUPAC name of CH3CH2C(=O)CH3?

Accepted Answer

2-butanone

Answer

The ketone carbonyl is at C2 of a four-carbon chain, giving 2-butanone (also called methyl ethyl ketone).

Question 3

Which of the following best describes the inductive effect of a fluorine atom on an adjacent carboxylic acid?

Accepted Answer

Electron withdrawal via σ-bonds, increasing acidity

Answer

Fluorine's high electronegativity withdraws electron density through σ-bonds, stabilizing the carboxylate anion and increasing acidity.

Question 4

The reaction of an aldehyde with two equivalents of an alcohol in acid gives which product?

Accepted Answer

Acetal

Answer

Two alcohols condense with an aldehyde under acid catalysis to form an acetal with loss of water.

Question 5

Which of these aromatic substituents is an ortho/para director that deactivates the ring?

Accepted Answer

–Cl

Answer

Halogens direct ortho/para via lone-pair resonance donation but deactivate the ring by strong inductive electron withdrawal.

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