Organic II Tests

Question 1

Describe the [Ag(NO3)2]+ (silver nitrate) test for Aldehydes

Answer 1

Observation: If Aldehyde is present, a silver mirror forms which coats the inside of the test tube

Equation: CH3CHO + 2Ag+ + H2O –> CH3COOH + 2Ag + H+

Question 2

Describe the Fehling’s (blue Cu2+) test for Aldehydes

Answer 2

Observation: Blue Cu2+ changes to red solution of Cu2O

Equation:
CH3CHO + 2CU2+ + 2H2O –> CH3COOH + CU2O + 4H+

Question 3

Describe the Iodoform tests for methyl Ketones and Ethanal.

Answer 3

Reagents: Iodine & NaOH
Conditions: Warm gently
Observation: Formation of a yellow crystalline precipitate

Equation: CH3COCH3 + 3I2 + 4NaOH –> CHI3 + CH3CH2COONa + 3Na2 + 3H20

Question 4

Describe one way to test for a Carboxylic Acid

Answer 4

Reagent: Sodium Carbonate

Observation: Effervescence
+ CO2 turns limewater cloudy

Question 5

Describe the 2,4-DNPH test for Carbonyl compounds.

Answer 5

Observation: If Carbonyl present, orange solution turns into orange precipitate.