The purpose of this experiment is to find out what is the lowest molarity of starch which gives a positive result to the iodine test.

Authors Avatar by choonyik (student)

Introduction: The purpose of this experiment is to find out what is the lowest molarity of starch which gives a positive result to the iodine test.

Hypothesis: This is a simple test which shows the present of starch.  When iodine solution is mixed with starch it turns from brown to dark blue.  As this happens with very small amounts of starch, iodine test is a sensitive one.  Starch forms as grains inside the living cells of plants.  Iodine solution penetrates into the starch most easily when the cell walls have been destroyed and it reacts most readily when the starch grains are swollen.  Both these things happen when plant foods are cooked.

Materials: Test Tubes, Test Tube Rack, Glass Rod, Dropper, Measuring Cylinder, Water, Syringe, Iodine Solution, Starch Solution, Beaker

Join now!

Methods:

 A serial dilution of starch solution is made as follows:

Place 5 clean test tubes in a test tube rack.

Place 10 cm³ of 1٪ starch solution in the first test tube by using a measuring cylinder.

1 cm³ of the solution has been taken out from the first test tube and place it in the second test tube by using a syringe.

 9 cm³ of water is added into the second test tube using a measuring cylinder and stir it with a glass rod. The ...

This is a preview of the whole essay