Why do we boil the leaf in alcohol when we are testing it for starch?

Extra information:

The iodine test can determine whether or not leaves contain starch (carbohydrate).

Here are the procedures for determining whether or not leaves contain starch:

Step 1: Collect a green leaf from a plant that has been in direct sunlight for at least a few hours.

Step 2: Half-fill a beaker with water and bring it to a boil.

Step 3: Place the leaf in a pot of boiling water and let it sit there for a few minutes to soften the cell wall.

Step 4: Boil the leaf in alcohol to extract the chlorophyll.

Step 5: Immerse the leaf in hot water to loosen its cells.

Step 6: Next, test the leaf for starch by dropping a few drops of iodine solution onto it.

A blue-black hue develops on the leaf once iodine is added, indicating the presence of starch in the sample.