Organic Chemistry Flashcards

Which of the following is the strongest acid?

Answer: Acetic acid (pKa ~4.75)

Acetic acid has the lowest pKa (~4.75), making it the strongest acid among the options because its conjugate base (acetate) is resonance-stabilized.

What happens to optical rotation when equal amounts of two enantiomers are mixed?

Answer: Rotation is zero (racemic mixture)

A 50:50 mixture of enantiomers is called a racemic mixture and shows zero net optical rotation because the rotations cancel.

Which reagent is used to distinguish an aldehyde from a ketone in Tollens' test?

Answer: Silver ammonia complex [Ag(NH3)2]+

Tollens' reagent ([Ag(NH3)2]+) oxidizes aldehydes to carboxylic acids, depositing a silver mirror; ketones do not react.

In the Fischer esterification reaction, which bond in the ester product comes from the alcohol?

Answer: The alkyl C–O bond (O from alcohol)

In Fischer esterification, the oxygen in the ester's alkyl–O bond is derived from the alcohol (confirmed by isotope labeling studies).

Which type of organic reaction does ozonolysis (O3 followed by Zn/H2O) perform?

Answer: Cleaves a C=C double bond to give carbonyl compounds

Ozonolysis cleaves C=C double bonds; reductive workup (Zn/H2O) gives aldehydes or ketones depending on substitution.

Which factor most stabilizes a carbocation?

Answer: Hyperconjugation and inductive donation from alkyl groups

Carbocations are stabilized by alkyl groups through hyperconjugation and positive inductive effects, explaining the order: tertiary > secondary > primary.

What is the hybridization of the carbon atoms in a C≡C triple bond?

Answer: sp

Each carbon in a triple bond forms two σ bonds (one to the other carbon, one to a substituent) using sp orbitals, leaving two unhybridized p orbitals for the two π bonds.