Organic Chemistry Flashcards

Which reagent converts a primary alcohol to an aldehyde without over-oxidizing to a carboxylic acid?

Answer: PCC (pyridinium chlorochromate)

PCC oxidizes primary alcohols to aldehydes and stops there because it is a mild oxidant used in non-aqueous conditions.

What is the major product when 2-butene undergoes acid-catalyzed hydration?

Answer: 2-butanol

Markovnikov addition of water across the double bond of 2-butene places the OH on the more substituted carbon, giving 2-butanol.

Which spectroscopic feature is most diagnostic for a carbonyl group (C=O) in IR spectroscopy?

Answer: Strong absorption near 1700 cm⁻¹

The C=O stretch appears as a strong, sharp absorption near 1700 cm⁻¹ (exact position varies with functional group).

In an E2 elimination reaction, the hydrogen and leaving group must be in what geometric relationship?

Answer: Anti-periplanar

E2 requires a concerted, single-step mechanism where H and the leaving group must be anti-periplanar (180°) to allow orbital overlap.

Which of the following compounds is aromatic?

Answer: Pyridine

Pyridine is aromatic because it is planar, fully conjugated, and has 6 π electrons (4n+2, n=1) satisfying Hückel's rule.

What type of isomers are D-glucose and L-glucose?

Answer: Enantiomers

D-glucose and L-glucose are non-superimposable mirror images, making them enantiomers.

Which reaction mechanism involves a planar carbocation intermediate and racemization of the product?

Answer: SN1

SN1 proceeds via a planar sp2 carbocation; nucleophilic attack from both faces leads to racemization.