Case: Aldehydes and ketones are important organic compounds with a carbonyl group (C=O) attached to a carbon atom. Aldehydes contain at least one hydrogen atom attached to the carbonyl group, while ketones have two alkyl or aryl groups attached to the carbonyl carbon. Common methods for the preparation of aldehydes and ketones include oxidation of primary and secondary alcohols, respectively, and the hydration of alkynes.
For example, acetaldehyde (CH₃CHO) can be prepared by the oxidation of ethanol, while acetone (CH₃COCH₃) is typically obtained by the oxidation of isopropyl alcohol (CH₃CH(OH)CH₃).
Questions:
Acetaldehyde (CH₃CHO) can be prepared by oxidizing:
The oxidation of a secondary alcohol results in the formation of:
Which of the following is a common reagent used in the oxidation of alcohols to aldehydes or ketones?
The carbonyl group in aldehydes is bonded to:
Case: Aldehydes and ketones are highly reactive due to the partial positive charge on the carbonyl carbon, making them susceptible to nucleophilic attack. The nucleophilic addition reactions are fundamental to the chemistry of aldehydes and ketones. One of the most common reactions is the addition of a hydride ion (H⁻) from a reducing agent such as sodium borohydride (NaBH₄), which reduces the carbonyl group to a hydroxyl group, converting the aldehyde or ketone into an alcohol.
For example, the reaction of acetone with NaBH₄ results in the formation of isopropyl alcohol (CH₃CH(OH)CH₃).
Questions:
The nucleophilic addition of hydride ions (H⁻) to an aldehyde or ketone results in the formation of:
Which of the following reagents is commonly used for the reduction of aldehydes and ketones to alcohols?
In the reaction of acetone with NaBH₄, the product formed is:
The addition of cyanide ion (CN⁻) to aldehydes and ketones results in the formation of:
Case: Carboxylic acids are compounds containing a carboxyl group (-COOH). They are known for their acidic properties due to the ability of the carboxyl group to donate a proton. Carboxylic acids can be prepared by the oxidation of primary alcohols and aldehydes. One common example is the oxidation of ethanol (CH₃CH₂OH) to acetic acid (CH₃COOH).
Carboxylic acids also undergo nucleophilic acyl substitution reactions to form their derivatives, such as esters, amides, and acyl chlorides.
Questions:
The oxidation of ethanol (CH₃CH₂OH) results in the formation of:
Carboxylic acids are known to exhibit:
The formation of an ester from a carboxylic acid is an example of:
The reaction between acetic acid and ammonia results in the formation of:
Case: Aldehydes, ketones, and carboxylic acids have distinct physical properties due to the presence of the carbonyl and carboxyl groups. Aldehydes and ketones typically have higher boiling points than alkanes of similar molecular weight, due to the dipole-dipole interactions between the carbonyl group and other molecules. Carboxylic acids, however, exhibit even higher boiling points due to the formation of hydrogen bonds between the carboxyl groups.
For example, acetic acid (CH₃COOH) has a higher boiling point than acetone (CH₃COCH₃), owing to hydrogen bonding between carboxyl groups.
Questions:
Carboxylic acids generally have a higher boiling point than aldehydes and ketones because:
Which of the following compounds has the highest boiling point?
The dipole-dipole interaction is primarily responsible for the boiling points of:
Acetone (CH₃COCH₃) has a lower boiling point than acetic acid (CH₃COOH) due to:
Case: Aldehydes, ketones, and carboxylic acids undergo several important reactions. For instance, aldehydes and ketones can react with reducing agents to form alcohols, as seen in the reduction of acetaldehyde to ethanol using sodium borohydride. On the other hand, carboxylic acids can undergo decarboxylation to form hydrocarbons. An example is the decarboxylation of acetic acid, which forms methane.
Carboxylic acids can also undergo reactions like esterification and reduction to alcohols.
Questions:
The reduction of acetaldehyde (CH₃CHO) results in the formation of:
The reaction between acetic acid and methanol is an example of:
The decarboxylation of acetic acid (CH₃COOH) results in the formation of:
Which of the following is a property of carboxylic acids?