Reactions With Carbonyl Groups Flashcards
What are aldehydes oxidised to?
Carboxylic acids
What symbol represents an oxidising agent?
[O]
What oxidising agent oxidised aldehydes?
Acidified potassium dichromate (VI)
How do we acidify potassium dichromate (VI)?
Add excess dilute sulfuric acid
What two tests distinguish an aldehyde from a ketone?
-Fehlings Test
-Tollens Reagent/Silver Mirror Test
How is Fehlings test used to identify an aldehyde?
- aldehyde warmed with Fehlings solution
- Brick red precipitate formed
- Cu (II) oxidises aldehyde and itself is reduced to Cu (I)
How is Tollens Reagent/ The silver mirror test used to identify an aldehyde?
- Aldehyde warmed with Tollens Reagent
- Metallic silver formed, produced mirror on inside of test tube
- Ag+ reduced to metallic silver
What equation shows how Tollens Reagent is reduced to metallic silver?
[Ag(NH3)2]+ + e- > Ag + 2NH3
What is a hydroxynitrile?
contains hydroxyl and nitrile group
Which is the highest priority group between hydroxyl and nitrile?
C=-N
How do we name hydroxynitriles?
name from nitrile, including C in C=-N bond as the start of the carbon chain
What is the symbol for a cyanide ion?
:CN-
What will the reaction of a cyanide ion and aldehyde produce?
Hydroxynitrile
Racemic mixture of two optical isomers (enantiometers)
Why can nucleophillic addition lead to a racemic mixture with a cyanide ion?
:CN- can attack from above and below planar C=O
How can an optical isomer arise in a hydroxynitrile?
-chiral carbon
-asymmetrical
-two different R groups