Organic Chemistry: Aldehydes and Ketones

What is the functional group characteristic of aldehydes?

Which reagent can be used to test for the presence of aldehydes?

What do ketones produce when tested with Tollen’s reagent?

Which reducing agent is commonly used in the reduction of aldehydes and ketones?

From which type of alcohols are aldehydes formed during oxidation?

What type of compound do ketones produce during their oxidation?

What is the result of the nucleophilic addition reaction involving KCN?

Which of the following statements is true about secondary alcohols in terms of their oxidation products?

Aldehydes

Characterized by the -CHO functional group, containing a carbonyl group (C=O).
Formed by the initial oxidation and distillation of primary alcohols (1° alcohols).
Readily oxidize further to produce carboxylic acids in the presence of acidified potassium dichromate.
Tested using Tollen's reagent or Fehling's solution, producing a positive result in both tests if present.

Ketones

Identified by the -C=O functional group, a carbonyl group.
Produced by the oxidation of secondary alcohols (2° alcohols) with acidified potassium dichromate.
Do not further oxidize and do not react visibly with Tollen's reagent or Fehling's solution.

Reduction

The oxidation reactions leading to aldehydes and ketones can be reversed via reduction reactions.
These reactions employ a reducing agent, typically NaBH4, and represent an example of nucleophilic addition.
The reducing agent (NaBH4) supplies the H:- nucleophile, while a H+ ion is also required, making an aqueous environment essential.

Hydroxynitriles

Nucleophilic addition reactions can occur with the :CN:- nucleophile.
This reaction constitutes a synthesis process, extending the carbon chain by one carbon atom.
The resulting product is a hydroxy-nitrile.
KCN (potassium cyanide) is frequently used to furnish the nucleophile instead of HCN (hydrogen cyanide) due to the difficulty of storing HCN as a gas.

HCN

HCN is reactive and forms hazardous byproducts.

This quiz covers the key concepts of aldehydes and ketones, focusing on their chemical structures, formation, oxidation, and reduction reactions. It also addresses the methods for testing these compounds, such as Tollen's reagent and Fehling's solution. Test your knowledge on these important organic compounds.