Aldehyde And Ketones Flashcards
What is a carbonyl group
C=O
What can aldehydes be oxidised to and what is the reagent
Carboxylic acid
Reagent: excess acidified potassium dichromate
How do we make tollens reagent
- Silver nitrate
- Add a few drops of NaOH until you see a pale brown ppt
- Add a few drops of dilute ammonia until ppt dissolves
Why do we use a water bath when we add an aldehyde or ketone to tollens reagent
Aldehyde and ketones are flammable, so it’s best to use a water bath instead of a busen burner
What kind of agent Is fehling solution
What is a positive result
Oxidising agent
Contains Cu2+ ions
Goes from blue solution to brick red precipitate
What happens if we reduce a
- Aldehyde
- Ketone
Aldehyde turns into a primary alcohol
Ketone turns into a secondary alcohol
What reducing agent do we use to reduce aldehyde and ketones
NaBh4
Sodium borohydride
How do we represent a reducing agent
[H]
Make sure to balance it
What is the mechanism called when you reduce an aldehyde or ketone into an alcohol
Nucleophilic addition
What compound do we form when we react potassium cyanide with a carbonyl group
Hydroxynitile
This has an OH group and a CN
Why do we use KCN instead of HCN
KCN is a solid do it’s easier to handle whereas HCN is a gas
What are the risks of using KCN
How can we reduce them
A risk is …
When it reacts with air it can produce a toxic gas HCN
How to reduce risks
Wear gloves
Wear safety glasses
Wear a lab coat to prevent clothing contamination
Use a fume cupboard or somewhere well ventilated
