Home /
Expert Answers /
Chemistry /
on-the-reactions-of-aldehydes-and-ketones-experiment-answer-these-questions-questions-1-what-pa332
(Solved): On the Reactions of Aldehydes and Ketones experiment.. answer these questions QUESTIONS 1. What ...
On the Reactions of Aldehydes and Ketones experiment.. answer these questions
QUESTIONS 1. What conclusions can you draw from the results of your tests concerning the reactivity of compounds containing the phenyl group , as compared with the corresponding methyl or ethyl compounds? Make as many comparisons as possible. 2. How does formaldehyde compare in reactivity with the other aliphatic aldehydes? 3. What test would you select for distinguishing between an aldehyde and an a-hydroxy ketone? 4. Only one of the above tests could be used to distinguish between the compounds: and (acetophenoneand propiophenone). What is the test? 5. How would you proceed to prepare pure acetone, starting with the pure, crystalline bisulfite addition product? 6. Outline the experimental procedure which you would use to separate a mixture of pentanone-2 (b.p. 1020) and pentanone-3 (b.p. 1010). 7. Suppose that it is desired to separate a mixture of an aldehyde and a ketone which does not form a bisulfite addition product, and suppose that they are both solids; how would you proceed? (Recall the procedure used in Experiment 6.) 8. How would you test a sample known to be one of the following compounds: hexanol-1, hexanol-2, or hexanone-2?
Expert Answer
1.Based on the results of tests, several conclusions can be drawn regarding the reactivity of compounds containing the phenyl group (C?H??) compared to the corresponding methyl or ethyl compounds:Electron density: The phenyl group is electron-rich due to the presence of the delocalized ? electrons in the benzene ring. This high electron density makes phenyl compounds more nucleophilic compared to methyl or ethyl compounds. The presence of the ? electrons allows for resonance stabilization and enhances reactivity. Nucleophilic aromatic substitution: Phenyl compounds are more susceptible to nucleophilic aromatic substitution reactions compared to methyl or ethyl compounds. The presence of the phenyl group facilitates the attack of nucleophiles at the electrophilic carbon in the ring, leading to substitution reactions. In contrast, methyl or ethyl compounds typically do not undergo nucleophilic aromatic substitution reactions. Electrophilic aromatic substitution: Phenyl compounds are more reactive towards electrophilic aromatic substitution reactions compared to methyl or ethyl compounds. The delocalized ? electrons in the benzene ring of phenyl compounds act as a nucleophile and can attack electrophiles, allowing for the substitution of functional groups. Methyl or ethyl compounds are less reactive in this context. Stability of carbocations: When phenyl compounds undergo reactions involving the formation of carbocations, such as electrophilic aromatic substitution, the phenyl group stabilizes the resulting carbocation through resonance. The delocalization of ? electrons across the ring provides stability to the positive charge. In contrast, methyl or ethyl compounds lack this stabilizing effect, making carbocations less stable in their corresponding reactions. Oxidation reactions: Phenyl compounds are more susceptible to oxidation reactions compared to methyl or ethyl compounds. The presence of the phenyl group provides additional sites for oxidation, such as the carbon atoms adjacent to the ring. Methyl or ethyl compounds, lacking this additional reactivity, are generally less prone to oxidation. Acidity/basicity: Phenyl compounds are generally less acidic or basic compared to methyl or ethyl compounds. The delocalization of ? electrons in the phenyl ring decreases the availability of electrons for protonation or deprotonation, making phenyl compounds less acidic or basic in nature. Steric hindrance: The bulkiness of the phenyl group can introduce steric hindrance in certain reactions, limiting accessibility to reactive sites. In contrast, methyl or ethyl groups are smaller and generally do not impose significant steric hindrance.