Org Chem Unknown Analysis Guide
Classification for Functional Groups
Alcohols
Lucas test
(Differentiates primary, secondary, and tertiary alcohols)
Reagent: ZnCl2 in conc. HCl
Observation: Rate of reaction (tertiary alcohol> secondary alcohol> primary alcohol)
Procedure: 2mL Lucas Reagent in test tube+ 3-4 drops of alcohol, stopper, shake vigorously, NOTE time required (less than 10m mins only) to form an emulsion or separate layers.
Oxidation
(Confirms if alcohol is oxidizable: presence of H in C-OH bond)
Reagent: Neutral KMnO4
Observation: purple color ( brown ppt
Procedure: 5 drops test sample in test tube+ 1 drop dilute neutral KMnO4, if NO DECOLORIZATION warm mixture.
Primary Alcohol( carboxylic acid
Secondary Alcohol( ketones
Tertiary( none
Phenols
Reaction with bromine/water
(Confirms if phenol compound)
Reagent: bromine in H2O
Observation: Disappearance of orange-brown bromine color, then formation of white precipitate
Procedure: 3 drops phenol soln on test tube+ Br in H2O drop by drop while shaking, observe formation of ppt
Oxidation by KMnO4
(Confirms if phenol compound)
Reagent: aqueous neutral KMnO4
Observation: purple color( brown color (formation of quinone)
Procedure: 3 drops phenol soln on test tube+ 1 drop aqueous neutral KMnO4, observe decolorizaton
Reaction with Ferric Chloride
(Confirms if phenol compound)
Reagent: FeCL3 solution
Observation: Complex formation (deep colored compounds)
Procedure: 3 drops of phenol soln in test tube + 1 drop FeCl3 soln
Aliphatic and Aromatic Hydrocarbons/ Alkenes
Bromination in Light (Free Radical Bromination)
(Reacts with alkanes)
Reagent: Br2 in H2O
Observation: decolorization, brown ( colorless
Procedure: 2 drops of test compound in test tube+ 1 drop 0.05 M Br2 in H2O, shake well, record observations
Bromination in Dark (Electrophilic Addition Halogenation)
(Reacts with alkenes)
Reagent: Br2 in H2O
Observation: decolorization, brown ( colorless
Procedure: 2 drops of test compound
Alcohols
Lucas test
(Differentiates primary, secondary, and tertiary alcohols)
Reagent: ZnCl2 in conc. HCl
Observation: Rate of reaction (tertiary alcohol> secondary alcohol> primary alcohol)
Procedure: 2mL Lucas Reagent in test tube+ 3-4 drops of alcohol, stopper, shake vigorously, NOTE time required (less than 10m mins only) to form an emulsion or separate layers.
Oxidation
(Confirms if alcohol is oxidizable: presence of H in C-OH bond)
Reagent: Neutral KMnO4
Observation: purple color ( brown ppt
Procedure: 5 drops test sample in test tube+ 1 drop dilute neutral KMnO4, if NO DECOLORIZATION warm mixture.
Primary Alcohol( carboxylic acid
Secondary Alcohol( ketones
Tertiary( none
Phenols
Reaction with bromine/water
(Confirms if phenol compound)
Reagent: bromine in H2O
Observation: Disappearance of orange-brown bromine color, then formation of white precipitate
Procedure: 3 drops phenol soln on test tube+ Br in H2O drop by drop while shaking, observe formation of ppt
Oxidation by KMnO4
(Confirms if phenol compound)
Reagent: aqueous neutral KMnO4
Observation: purple color( brown color (formation of quinone)
Procedure: 3 drops phenol soln on test tube+ 1 drop aqueous neutral KMnO4, observe decolorizaton
Reaction with Ferric Chloride
(Confirms if phenol compound)
Reagent: FeCL3 solution
Observation: Complex formation (deep colored compounds)
Procedure: 3 drops of phenol soln in test tube + 1 drop FeCl3 soln
Aliphatic and Aromatic Hydrocarbons/ Alkenes
Bromination in Light (Free Radical Bromination)
(Reacts with alkanes)
Reagent: Br2 in H2O
Observation: decolorization, brown ( colorless
Procedure: 2 drops of test compound in test tube+ 1 drop 0.05 M Br2 in H2O, shake well, record observations
Bromination in Dark (Electrophilic Addition Halogenation)
(Reacts with alkenes)
Reagent: Br2 in H2O
Observation: decolorization, brown ( colorless
Procedure: 2 drops of test compound