Document Text Contents
Page 4
O
C R
O
O
C R
C R
O
H2C O
HC O
H2C O
KOH
H
H
H
H2C O
HC O
H2C O
R C OK+ 3 + 3
Materials
• Oil
• Alcoholic sodium or potassium hydroxides(0.5 N)
• Sodium Chloride
• Concentrated hydrochloric acid
Procedure
1. Place 5 g of oil or fat, 1.0 g of sodium hydroxide and 25 ml of alcohol in round
flask.
2. Place the boiling stone at round flask for regulating the heating and reflux the
solution for 30 minutes at boiling water bath.
3. Warm the solution for evaporating the alcohol.
4. Cool the solution in a beaker of cold water.
5. Remove a small piece of the solid product (about the size of a pea) using a glass
stirring rod and dissolve it with 20 ml DW and observe the foam formed between
soap and water.
7. Ammonium Molybdate Test for Phosphate
The presence of free phosphate in acidic solution can be detected by adding a molybdate to
the solution. Equation illustrates the pertinent reaction between phosphate and ammonium
molybdate solution in the presence of nitric acid (HNO3).
HPO42–(aq) + 12MoO42–(aq) + 3 NH4+(aq) + 23 H3O+(aq) (NH4)3[P(Mo3O10)4] (yellow,s) + 35 H2O(l)
After a few minutes, the yellow ammonium molybdo-phosphate precipitates from the
reaction mixture. When lipids containing phosphate groups in their structures are added to a strong
acid solution such as the solution used here, the lipid hydrolyses, producing free phosphate. The
free phosphate then reacts as in Equation, forming a yellow precipitate.
Materials
1. Prepare an ice-water bath
2. Place 0.2 g of lecithin (ege yolk) in a washed , drained test tube
3. Add 3 ml of 6M nitric acid solution (HNO3).
O
C R
O
O
C R
C R
O
H2C O
HC O
H2C O
KOH
H
H
H
H2C O
HC O
H2C O
R C OK+ 3 + 3
Materials
• Oil
• Alcoholic sodium or potassium hydroxides(0.5 N)
• Sodium Chloride
• Concentrated hydrochloric acid
Procedure
1. Place 5 g of oil or fat, 1.0 g of sodium hydroxide and 25 ml of alcohol in round
flask.
2. Place the boiling stone at round flask for regulating the heating and reflux the
solution for 30 minutes at boiling water bath.
3. Warm the solution for evaporating the alcohol.
4. Cool the solution in a beaker of cold water.
5. Remove a small piece of the solid product (about the size of a pea) using a glass
stirring rod and dissolve it with 20 ml DW and observe the foam formed between
soap and water.
7. Ammonium Molybdate Test for Phosphate
The presence of free phosphate in acidic solution can be detected by adding a molybdate to
the solution. Equation illustrates the pertinent reaction between phosphate and ammonium
molybdate solution in the presence of nitric acid (HNO3).
HPO42–(aq) + 12MoO42–(aq) + 3 NH4+(aq) + 23 H3O+(aq) (NH4)3[P(Mo3O10)4] (yellow,s) + 35 H2O(l)
After a few minutes, the yellow ammonium molybdo-phosphate precipitates from the
reaction mixture. When lipids containing phosphate groups in their structures are added to a strong
acid solution such as the solution used here, the lipid hydrolyses, producing free phosphate. The
free phosphate then reacts as in Equation, forming a yellow precipitate.
Materials
1. Prepare an ice-water bath
2. Place 0.2 g of lecithin (ege yolk) in a washed , drained test tube
3. Add 3 ml of 6M nitric acid solution (HNO3).
