Carbonyl compounds Flashcards
What is the carbonyl group?
C=O
How do you name aldehydes?
-al suffix (C=O is on the end of a chain)
How do you name ketones?
-one suffix (designate number for which carbon C=O is on)
What kind of intermolecular forces do molecules with the carbonyl group have?
Permanent dipole-dipole due to the polar C=O bond
How soluble are they in water? what influences solubility?
Yes - forms hydrogen bonds between water molecules and oxygen of C=O. As chain length increases, solubility decreases.
What is the strongest bond in carbonyl compounds?
C=O
Why is the addition of HCN important?
Increases the length of the carbon chain by one carbon atom allowing more useful molecules to be made.
Will the product of HCN added to a carbonyl compound have optical isomers? Why?
Yes they will. In the aldehyde/ketone, the carbonyl carbon is planar, so the :CN- can attack from either above or below, forming two enantiomers.
What is the name of the product when HCN is added to a carbonyl compound?
Hydroxynitriles
What is Fehling’s solution? What colour is it?
Copper complex ions, blue
What happens when an aldehyde is added to Fehling’s solution?
Reduced to Cu+ ions —> colour change to brick red ppt
What happens when a ketone is added to Fehling’s solution?
No visible change —> stays blue
How do you test for a carbonyl compound?
Use Brady’s reagent — 2,4-dinitrophenylhydrazine
If a carbonyl compound is present orange ppt is formed
What is in Tollens’ reagent?
Silver complex ions in colourless solution
What happens when an aldehyde is added to Tollen’s reagent?
Silver mirror forms as Ag+ reduced to Ag (s)
What happens when a ketone is added to Tollen’s reagent?
No visible change
What is a reducing agent for aldehydes and ketones? What ions does this release in solution?
NaBH4 releases an H- ion
