Carbonyl compounds

Question 1

oxidation of primary alcohol

Answer 1

warmed with K2CrO7/H2SO4

produces aldehyde then carboxylic acid + water under reflux

Question 2

oxidation of secondary alcohol

Answer 2

warmed with K2CrO7/ H2SO4

produces ketone

Question 3

oxidation of tertiary alcohol

Answer 3

no reaction

Question 4

reduction of carbonyl

Answer 4

Reagent NaBH4

ketone to secondary alcohol

aldehyde to primary alcohol

Question 5

Nucleophilic addition with cyanide ion

Answer 5

Reagent HCN

produces hydroxynitrile

Question 6

Reaction test for aldehyde and ketone

Answer 6

Brady’s reagent(2,4,dinitrophenylhydrazine)

Produces orange precipitate
Purify by recrystallisation
Melting point comparison to table determines aldehyde or ketone

Question 7

Oxidation of aldehyde

Answer 7

H+/Cr2O72-
warm conditions
orange to green

Question 8

Identification of aldehde

Answer 8

Tollen’s reagent Ag(NH3)2+
warm gently in water bath 60
silver precipitation

Question 9

Why tollens produces silver mirror

Answer 9

Ag+(aq) reduced to Ag(s)

Aldehyde produces carboxylic acid

Question 10

Make tollens reagent

Answer 10

silver nitrate(aq) + aqueous sodium hydroxide(aq)
Add ammonia(aq)drop-wise until precipitated silver oxide