6.1.2 Carbonyl Compounds Flashcards
What is the carbonyl group?
C=O
What is functional group and general formula for an aldehyde?
RCHO (C=O, single bonded to H and R)
What is functional group for a ketone?
RCOR’ (C=O)
How do you name aldehydes?
-al suffix
How do you name ketones?
- one suffix (designate number for which carbon C=O is on)
What kind of intermolecular forces do molecules with carbonyl group have? Why?
Permanent dipole-dipole due to polar C=O bond
How soluble are they 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 polarity of bond
What is strongest bond in carbonyls?
C=O
Why is addition of HCN important?
Increases the length of the carbon chain by one carbon atom allowing more useful molecules to be made.
Will product of HCN added to a carbonyl 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 enatiomers
What is name of product when HCN is added to a carbonyl?
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?
Use 2,4-DNP
If a carbonyl is present an orange precipitate is formed
What is in Tollen’s 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 carbonyls?
NaBH4- releases H- ions
How do you convert aldehyde to form carboxylic acid?
Oxidation using Cr2O7 ^2-/ H+
