Scheme PH. Org. Chem. 2 spring 2024.pptx

1. Scheme for liquid unknowns
Formic acid / Acetic acid
Oxidation
Decolorization of violet color Violet color
Formic acid  Acetic acid
a) 1 ml Unknown
b) 2 ml
Na2CO3
c) Drops
KMnO4
Acetic acid has vinegar like
odor

2. Scheme for solid unknowns Acids:
Oxalic acid/ Benzoic acid / Salicylic acid
1) Acidity
No Effervescence Effervescence
Salt of acid  Acid
a) 2 ml Na2CO3
b) Heat gently c) 0.1 g of unknown (
1
4
spatula)
2) Solubility in H2O
c) Shake vigorously
(5 min)
b) 3 ml H2O
a) 0.1 g of unknown
(
1
4
spatula)
Salts:
Sodium or Ammonium Benzoate / Sodium or Ammonium
Salicylate / Sodium or Ammonium Oxalate / Sodium or
Ammonium Formate / Sodium or Ammonium Acetate
Soluble in H2O
 Aliphatic acid
Oxalic acid
Add 1ml CaCl2 
white ppt
Insoluble in H2O
 Aromatic acid
Benzoic acid / Salicylic acid
b) 1 ml FeCl3
a) 0.1 g of unknown
(
1
4
spatula)
3) FeCl3
Violet color
 Salicylic acid
No Violet color
(yellow)
 Benzoic acid
b) 2 ml NaOH
a) 0.1 g of unknown
(
1
4
spatula)
Odor of NH3
 Ammonium salt
No odor of NH3
 Sodium salt
Cation
2) 30% NaOH test
Anion
a)Aqueous solution of unknown solid
0.1 g of unknown (
1
4
spatula) + 3 ml of H2O
(dissolve unknown)
Violet color
 Salicylate
No change in color (yellow)
 Oxalate
3) FeCl3
b) 1 ml FeCl3
Buff ppt.
 Benzoate
Red color
 Formate / acetate
c) Drops
KMnO4
a)Aqueous solution
of unknown solid
4) Oxidation
Violet color
Decolorization
of violet color
 Acetate
b) 2 ml Na2CO3
 Formate