Aldehydes and ketones

Carbonyl compounds

what is the functional group for aldehydes and ketones

CHO

where is the functional group located on aldehydes

at the end of the molecule

where is the carbonyl group located on ketones

in the middle

why do carbonyl compounds have lower boiling points than alcohols

have no polar OH bond meaning no hydrogen bonds can be formed

how are carbonyl compounds still able to dissolve in water

they can form hydrogen bonds with water due to a lone pair of electrons on the oxygen of the C=O group

what can aldehydes be oxidised to

carboxylic acids

what reagent is used in oxidation of aldehydes

acidified potassium dichromate

what colour change occurs during the oxidation of aldehydes to carboxylic acids

orange to green

why are aldehydes oxidised but ketones aren’t

the H attached to the carbonyl group in an aldehyde is weakly acidic, so it is easily displaced

what type of alcohols are aldehydes reduced to

primary

what type of alcohols are ketones reduced to

secondary

what is the reagent for reduction of carbonyl compounds

LiAlH4

what are the reaction conditions for the reduction of carbonyl compounds

dry ether

what type of reaction is the reduction of carbonyl compounds

nucleophilic addition

what is the benefit of forming hydroxynitriles from carbonyl compounds

extends the carbon chain

what type of reaction is the formation of hydroxynitriles from carbonyl compounds

nucleophilic addition

what reagent is used in the reaction to form hydroxynitriles

HCN

what issue with using HCN to form hydroxynitriles

toxic

how can the issue of HCN being toxic be overcome

generate the nucleophile in situ by mixing NaCN with dilute sulfuric acid

what can 2,4-DNPH be used to identify

carbonyl compounds

what is 2,4-DNPH dissolved in

methanol and concentrated sulfuric acid

what forms as a positive result for 2,4-DNPH

bright orange ppt

what happens to the ppt formed from 2,4-DNPH to identify the compound

filtered then purified by recrystallisation, the melting point of the derivative is measured and compared to known values

what is tollen’s reagent

ammonia + silver nitrate

what is a positive reaction with tollen’s reagent

silver mirror

do aldehydes or ketones have a positive result with tollen’s reagent

aldehydes

what colour change happens with fehlings reagent

blue to brick red

does fehling’s form a positive result with aldehydes or ketones

aldehydes

what does the iodform reaction test for

methyl ketone group

what is the reagent for the idoform reaction

iodine and warm sodium hydroxide

what forms as a positive result for the idoform reaction

cream ppt

what smell will the ppt from the idoform reaction have

antiseptic

what is the name and formula of the ppt formed from idoform reaction

CHI3, triiodomethane

how can we identify triiodomethane

collecting crystals and determining melting point