aldehydes and ketones Flashcards
What functional group is characteristic of aldehydes?
C=O functional group at the end of the carbon chain
Aldehydes are named with the suffix -al.
What functional group is characteristic of ketones?
C=O functional group in the middle of the carbon chain
Ketones are named with the suffix -one.
What is the solubility characteristic of short-chained aldehydes and ketones?
Soluble in water
The polar carbonyl group can form hydrogen bonds with water.
How do longer chains of aldehydes and ketones behave in water?
Not soluble in water
Longer chains (5C+) are less polar and the carbonyl group has less of an effect.
What types of intermolecular forces do aldehydes and ketones exhibit?
Van der Waals forces and dipole-dipole forces.
Why is the C=O bond in carbonyl compounds significant?
Almost all reactions involve the C=O bond due to its strong polarity.
What type of reactions do carbonyl compounds typically undergo?
Nucleophilic additions.
What is the oxidation reaction of an aldehyde?
ALDEHYDE + [O] → CARBOXYLIC ACID in the presence of an acid catalyst.
Can ketones be oxidized?
No, ketones cannot be oxidized.
What is Fehling’s test used for?
To distinguish between aldehydes and ketones.
What occurs when an aldehyde is warmed with Fehling’s solution?
A brick red precipitate of copper(I) oxide is produced.
What is the outcome of Tollens’ reagent when reacted with an aldehyde?
A metallic silver mirror is formed.
What does Tollens’ reagent contain?
[Ag(NH3)2]+ complex ion.
What is the general reaction for the reduction of carbonyl compounds?
ALDEHYDE/KETONE + NaBH4 (aq) → ALCOHOL.
What type of alcohol do aldehydes reduce to?
Primary alcohols.
What type of alcohol do ketones reduce to?
Secondary alcohols.
What is catalytic hydrogenation?
Addition of hydrogen with a nickel catalyst at high pressure.
What is produced when an aldehyde is treated with KCN?
Hydroxynitriles.
What type of mixture is produced when an aldehyde or unsymmetrical ketone reacts with KCN?
Racemic mixture or two optical isomers (enantiomers).
What safety precautions should be taken when using KCN?
Wear gloves and goggles, use in a fume cupboard.
What is the role of NaBH4 in the reduction of carbonyl compounds?
It provides the source of hydride ions (H-).
Fill in the blank: Ketones give ______ to Fehling’s test.
no reaction.
