Test for Starch in a Leaf Flashcards
What is the first step?
Place the leaf in boiling water for 30 seconds – this kills it, stopping any further chemical reactions.
What is the second step?
Place the leaf in boiling ethanol – removes the chlorophyll making the leaf paler in colour.
What is the third step?
Dip the leaf in water – this softens it.
What is the fourth step?
Spread the leaf onto a white tile and add iodine to test for the presence of starch.
What is the result if starch is present?
If starch is present the iodine will change from yellow-brown to blue-black.
What is the result if starch is absent?
If starch is absent the iodine will remain yellow-brown.
What are some safety notes?
As well as wearing goggles throughout the experiment, ensure that the ethanol is not exposed to a naked flame during step 2, as it is highly flammable.
