aldehydes and ketones Flashcards
carbonyl group
C=O
what is the general formula of aldehyde
RCHO
functional group for ketone
C=O in the middle of a carbon chain
how to name aldehydes
-al suffix
how to name ketones
-one suffix
what kind of intermolecular forces do molecules with carbonyl group have
permanent dipole-dipole due to C=O
how soluble are they in water
yes as form hydrogen bonds between water molecules and oxygen of C=O
which bond in carbonyl compounds is usually involved in reactions and why
C=O due to polarity of bond
what is the strongest bond in carbonyl compounds
C=O
why is addition of HCN important
increases length of carbon chain by one carbon atom - very useful
will product of HCN added to a carbonyl compound have optical isomers
yes
aldehyde/ketone, 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 (both OH and CN groups)
what is Fehling’s solution and what colour
copper complex ions
blue colour
what happens when aldehyde is added to brick red ppt
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
what is in tollen’s reagent
silver complex ions, 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 another oxidising agent for alcohols and aldehydes and what colour change
acidified potassium dichromate (VI)
H2SO4 and Kr2Cr2O7
colour change orange to green
what is a reducing agent for aldehydes and ketones? what ions does this release in solution
NaBH4
sodium tetrahydridoborate (III) releases an H- ion
