aldehydes and ketones Flashcards
general formula aldehydes and ketones
CnH2nO
fuctional group
aldehydes and ketones both contain the carbonile bond (=O)
where is the functional carbonie bond on an aldehyde
end of chain
where is the functional carbonile bond on ketones
middle of chain
what are aldehydes and ketones with the same number of carbon atoms, in relation to eachother
functional group isomers
how can aldehydes and ketones be prepared
oxidation of alcohols
what are aldehydes readily oxidised to
carboxylic acids
what 3 reagents can be used to oxidise an aldehyde to a carboxylic acid
- acidified potassium dichromate and warm
- fehlings solution and warm
- tollens reagent and warm
what observations with acidified potassium dichromate and warm and aldehyde
orange>green
what observations with fehlings solutions and warm and aldehyde
blue solution>brick red ppt
what observations with tollens reagent and warm and adlehyde
silver mirror
what are tollens reagent and fehings solutions used as
chemical tests to distinguish between aldehydes and ketones
how are tollens and fehlings used to distinguish between aldehydes and ketones
ketones cannot be further oxidised and will not react with either tollens reagent/fehlings solution
what complex ion does tollens reagent contain
Ag(NH3)2+
why is a silver mirror seen when an aldehyde is warmed with tollens
the aldehyde is oxidised to a carboxylic acid and the silver ions are reduced to silver metal
equation for reaction of aldehyde with tollens
RCOH+(O)>RCOOH
Ag+aq>Ags
what does (O) represent in equation for aldehyde and tollens
oxidising agent- tollens
which ions does fehlings solution contain
cu2+
why is a brick red ppt seen when an aldehyde is warmed with fehlings
aldehyde is oxidised to a carboxylic acid and the copper ions are reduced to copper 1 oxide (cu2o)
what does the presence of the delta+ c atom in aldehydes and ketones mean
theyre susceptible to attack by nucleophiles
why do aldehydes and ketones have a delta+ c atom
polar C=O bond
what is a nucleophile
an electron pair donor
how can the nucleophile attach the delta+ carbon
forming a new covalent bond, an addition reaction then occurs across the double bond
what can aldehydes and ketones be reduced to
alcohols
