(Draw in LHS of record)
EXPERIMENT: 3 SURFACE CHEMISTRY: - PREPARATION OF LYOPHILIC SOL STARCH
(WRITE IN RHS) EXPERIMENT: 3 Date :
SURFACE CHEMISTRY: - PREPARATION OF LYOPHILIC SOL STARCH
AIM:-
To prepare a colloidal solution (sol) of starch
THEORY:-
Lyophilic sols have greater affinity between dispersed phase and dispersion medium e.g., egg albumin, gum and starch have greater affinity for water. The formation of solution is accelerated by heating starch and water at about 1000C. They are more stable and is not affected by the presence of any electrolytic impurity.
APPARATUS and CHEMICALS REQUIRED:-
Beakers (250ml and 50ml) , glass rod, funnel, filter paper, pestle and mortar, tripod stand, wire gauze and burner.
Soluble starch (500mg) and distilled water.
PROCEDURE:-
1. Take 500mg of starch in a mortar and add few ml of distilled water.
2. Grind the starch to make a thin paste and transfer this paste to a 50ml beaker.
3. Take about 100ml of distilled water in a 250ml beaker and heat the beaker so that water starts boiling.
4. Pour the paste slowly with stirring into boiling water in the beaker
5. Continue boiling for about 10minutes and then allow the beaker to cool.
6. Filter the contents of the beaker through a filter paper, fixed in a funnel. Label the filtrate STARCH SOL.
RESULT:-
Lyophilic colloidal solution of starch was prepared in the laboratory.
PRECAUTIONS
1. The apparatus used for preparing should be absolutely clean.
2.Distilled water should be used for preparing sol.
3. Starch should be converted into a fine paste before adding to boiling water and should be added as a thin stream with constant stirring.
