Carbonyl Compounds

Question 1

Nucleophilic addition of HCN to aldehyde

Answer 1

HCN and trace NaOH/CN (aq) to generate catalyst, cold

Question 2

Reduction of aldehyde/ketone to form primary alcohol (hint: most reduction reactions involve the same few sets of reactants)

Answer 2

H2 with Ni cat, heat under pressure
LiAlH4 in dry ether
NaBH4 in methanol solution

Question 3

Oxidation of aldehydes (not ketones) to carboxylic acids

Answer 3

K2Cr2O7/KMnO4 in dilute H2SO4, heat under reflux

Question 4

Reaction with 2,4-DNPH

Answer 4

Orange ppt formed for aldehyde, benzaldehyde and ketone

Question 5

Reaction with Tollen’s reagent

Answer 5

Silver mirror formed immediately for all 3 except ketone

Question 6

Reaction with Fehling’s reagent

Answer 6

Reddish-brown ppt formed only for aliphatic aldehyde

Question 7

Iodoform test (using warm alkaline aqueous iodine)

Answer 7

Benzaldehydes definitely do not form pale yellow ppt

For the other 2, see if their structures fit