Aldehydes and Ketones Flashcards
1
Q
What is the functional group of aldehydes?
A
-CHO
2
Q
What is the redox behaviour of aldehydes?
A
- Reduced to primary alcohols
- Oxidised to carboxylic acids
3
Q
What is the redox behaviour of ketones?
A
- Reduced to secondary alcohols
- Cannot be oxidised
4
Q
How can you differentiate between aldehydes and ketones?
A
- Benedict’s and Fehling’s solution will turn from blue to brick red in the presence of an aldehyde, but do nothing with a ketone
- Tollen’s reagent will form a silver mirror in the presence of an aldehyde, by will stay clear with a ketone
5
Q
What four compounds contain a carbonyl group?
A
- Aldehydes
- Ketones
- Carboxylic acids
- Amides
6
Q
In nucleophilic addition to a carbonyl, which part of the molecule is ‘attacked’ by the
A
The carbon atom
7
Q
Why can a hydride ion not be freed?
A
It is too reactive
8
Q
What is produced when a cyanide ion is added to a carbonyl?
A
A hydroxynitrile
9
Q
Why is an acid required in the final step of the nucleophilic addition of cyanide to a carbonyl?
A
To neutralise the negative charge on the oxygen atom
10
Q
What compound is used as an H- source for hydride reduction?
A
Sodium borohydride
