sp\textsuperscript{2} hybridized, trigonal planar geometry

Question 1

Which hybridization and geometry best describes the carbon atom in a typical carbonyl group, as shown in the first image?

Accepted Answer

sp	extsuperscript{2} hybridized, trigonal planar geometry

Question 2

In the nucleophilic addition to a carbonyl compound (second image), what is the primary reason the nucleophile attacks the carbonyl carbon?

Accepted Answer

The carbonyl carbon is partially positive due to polarization of the C=O bond.

Question 3

Which reagent is most suitable for reducing carboxylic acids and esters to alcohols?

Accepted Answer

Lithium aluminum hydride (LAH)

Question 4

What is the oxidation number change for the carbon atom in a primary alcohol when it is oxidized to a carboxylic acid?

Accepted Answer

From $$-1 to$$ $$+3$$

Question 5

Why can't tertiary alcohols be oxidized under normal conditions?

Accepted Answer

They lack a hydrogen atom on the carbon bearing the hydroxyl group.

Question 6

Which reagent is used for mild oxidation of alcohols and is known for its unpleasant sulfur odor?

Accepted Answer

Swern oxidation reagent

Question 7

What is the main difference between sodium borohydride (NaBH	extsubscript{4}) and lithium aluminum hydride (LAH) as reducing agents?

Accepted Answer

LAH is stronger and reduces carboxylic acids and esters.

Question 8

In the Grignard reaction mechanism (third image), what is the role of the ether solvent?

Accepted Answer

It stabilizes the Grignard reagent by coordinating with magnesium.

Question 9

Which of the following statements about Grignard reagents is TRUE?

Accepted Answer

They are strong bases and react violently with acidic hydrogens.

Question 10

What is the product when a Grignard reagent reacts with an ester, followed by aqueous workup (see images 3-6)?

Accepted Answer

A tertiary alcohol

Question 11

Which step is necessary for the oxidation of aldehydes to carboxylic acids?

Accepted Answer

Hydration of the aldehyde

Question 12

Why is PCC (pyridinium chlorochromate) preferred for oxidizing primary alcohols to aldehydes?

Accepted Answer

It prevents overoxidation to carboxylic acids.

Question 13

Which organometallic reagent is more aggressive and pyrophoric compared to Grignard reagents?

Accepted Answer

Alkyl lithium reagents

Question 14

What is the regiochemistry of epoxide ring opening by Grignard reagents?

Accepted Answer

Attack occurs at the less substituted carbon.

Question 15

Which of the following is a limitation of Grignard reagents in organic synthesis?

Accepted Answer

They react with water and acidic hydrogens, interfering with intended reactions.

Question 16

What is the purpose of protecting alcohols during multistep organic synthesis?

Accepted Answer

To prevent unwanted reactions with strong bases or nucleophiles.

Question 17

Which reagent is used for strong oxidation and has a complicated mechanism?

Accepted Answer

Potassium permanganate (KMnO	extsubscript{4})

Question 18

In a retrosynthetic analysis, which functional group transformation is commonly used to plan the synthesis of alcohols from esters?

Accepted Answer

Reduction of esters to alcohols using organometallic reagents

Question 19

Which of the following statements about the oxidation of secondary alcohols is correct?

Accepted Answer

Secondary alcohols can be oxidized to ketones because they have one hydrogen on the carbon bearing the hydroxyl group.

Redox Reactions and Organometallic Chemistry: Alcohols, Carbonyls, and Synthesis

Study Guide - Practice Questions