Final answer:
The products of reacting aldehydes or ketones with metal hydride reagents are alcohols through nucleophilic addition. Aldehydes are easily oxidized to carboxylic acids, differentiating them from ketones, which resist oxidation. These compounds are used in various industries, including fragrances and plastics.
Step-by-step explanation:
The products of reacting aldehydes or ketones with metal hydride reagents are primarily alcohols. This reaction is a type of nucleophilic addition, where a hydride ion (H⁻) is added to the electrophilic carbon of the carbonyl group (C=O). In catalytic hydrogenation, hydrogen (H₂) reduces aldehydes and ketones to alcohols in the presence of a catalyst such as finely divided nickel (Ni), palladium on carbon (Pd/C), or platinum on carbon (Pt/C).
Aldehydes and ketones both contain the carbonyl functional group, but they behave differently in oxidation reactions. Aldehydes can be easily oxidized to carboxylic acids, as shown in the reaction 2RCHO + O₂ → 2RCOOH, while ketones are generally resistant to oxidation. This difference is key for chemists when identifying these compounds, as it allows for them to distinguish between aldehydes and ketones using agents like Tollens' reagent.
Beyond these reactions, aldehydes and ketones can also engage in glycosidic bond formation with alcohols to produce hemiacetals and further react to form acetals. This adaptability in reactions indicates the versatility of aldehydes and ketones, allowing for various applications in industry and research, including use in fragrances, plastics, and as solvents.