17B- Carbonyl Compounds

Question 1

How can a carbonyl compound be identified with 2,4 DNP?

Answer 1

• an orange precipitate forms
• the insoluble impurities and filtered.
• the filtrate is recrystallised
• the crystals are heated and melting point is recorded.
• compare values of melting point to identify carbonyl compound

Question 2

Explain how iodoform test works

Answer 2

• tests for methyl ketones, ethanal, ethanol, methyl secondary alcohol
• reagent heated with alkaline solution of iodine
• yellow precipitate forms