Aldehydes and Ketones Flashcards
What is the carbonyl group?
C=O
What is the functional group and general formula for an aldehyde?
RCHO (C double bonded to O, single bond to H and R)
What is the functional group for a ketone?
RCOR’ (C double bonded to 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? Why?
Permanent dipole-dipole due to the polar C=O bond (O is delta -)
Are they soluble in water? What influences solubility?
Yes - form hydrogen bonds between water molecules and oxygen of C=O.
As C chain length increases, solubility decreases.
Which bond in carbonyl compounds is usually
involved in reactions? Why?
C=O, due to the polarity of the bond (large difference in electronegativity between C and O)
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 - very useful
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 (have OH and CN groups)
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