3.3.7-8 Optical Isomerism - Aldehydes & Ketones Flashcards
What is the definition of structural isomerism?
molecules with the same molecular formula but different structural formulae
What is the definition of stereoisomerism?
molecules with the same structural formula but different arrangement of atoms in space
Optical isomerism is a form of structural or stereo isomerism?
stereoisomerism
What are optical isomers?
non-superimposable mirror images
What is a chiral carbon?
A carbon atom bonded to four different groups
What do chiral molecules do to plane-polarised light?
rotate it
What is a racemic mixture?
A mixture which contains equal quantities of enantiomers?
What are enantiomers?
non-superimposable mirror images
What is meant by a sample which is enantiomerically pure?
A sample which contains only one optical isomer
What is another name for chiral centre?
stereogenic centre
Aldehydes and ketones are compounds which both contain which type of bond?
carbonyl bond
An aldehyde is a compound where the carbonyl bond is located where on the carbon chain?
at the end
A ketone is a compound where the carbonyl bond is located where on the carbon chain?
in the middle
What is observed when Tollen’s reagent is mixed with an aldehyde?
silver mirror forms
What is observed when Tollen’s reagent is mixed with a ketone?
No visible change
What is observed when Fehling’s reagent is mixed with an aldehyde?
brick-red precipitate forms
What is observed when Fehling’s reagent is mixed with a ketone?
No visible change
What type of product is formed when an aldehyde is reduced?
primary alcohol
What type of product is formed when a ketone is reduced?
secondary alcohol
Name the mechanism for the reduction of an aldehyde or ketone?
nucleophilic addition
What reagent is used to reduce an aldehyde or ketone?
NaBH4
What condition is needed in the reduction of an aldehyde or ketone
acidic solvent
Name the product formed when butanone is reduced with NaBH4
butan-2-ol
Name the product formed when pentanal is reduced with NaBH4
pentan-1-ol
What type of product is formed when an aldehyde or ketone is reacted with KCN?
Hydroxy nitrile
Name the product formed when butanal is reacted with KCN
2-hydroxypentanenitrile
