What is the result of the Test for the presence of starch in a leaf?

Answer 1

Method

Half fill a beaker with boiling water and add a large test tube that is a

quarter full of ethanol. Allow the ethanol to come to the boil. Do not heat

the ethanol in a Bunsen burner flame. This is not safe because ethanol is

highly flammable.

Take a leaf that has been sitting in good light for at least a few days, and

soften on the boiling water for ten seconds or so. Then add to the ethanol

and allow to boil for about a minute until all the colour disappears from

the leaf.

Remove the leaf from the ethanol. Put it back in the hot water to soften for

10 seconds.

Spread the leaf out on a white tile and use the iodine solution to test for

starch A blue-black colour indicates starch is present.

This experiment can be repeated with leaves that have been left in the dark.

or have been deprived of carbon dioxide.

Answer 2

1. Put the leaf you want into a beaker of boiling water for about 10 seconds.

2. Then put your leaf into a test tube of ethanol and place back into the boiling water for about 10 minutes. BE CAREFUL ETHANOL IS A HIGHLY FLAMMABLE SUBSTANCE AND IF YOU ARE USING A BUNSEN BURNER TO HEAT THE WATER MAKE SURE THAT THE BUNSEN IS OUT WHEN YOU PLACE THE ETHANOL INTO THE BOILING WATER!!

3. Take the leaf out of the ethanol and wave the leaf around to and fro in the boiling water, (this will remove the ethanol from the leaf).

4. Place the leaf in a petri dish and cover the leaf in dilute iodine. The starch in the leaf will show up a blue-brown.

Answer 3

Please rephrase your question.
If I would have to answer this particular question, the answer would be: Positive.
There is starch in a leaf, unless you extract it by use of an anorganic substance*

*please edit this part

Answer 4

Take a leaf and boil it in a test tube filled with . This is done to kill the cell. The chlorophyll doesn't dissolve in water though.

Then put the leaf inside a test tube filled with alcohol. Place the test tube in a water bath over a Bunsen burner and boil the bath. This is done as a precaution because alcohol is highly inflammable.

When the alcohol turns green, then that means that the chlorophyll has come out of the leave. The leaf will turn white. Chlorophyll only dissolves in alcohol.

Take the leaf and rinse it under water as the leaf becomes very brittle on heating.

The leaf softens.

Take a white tile and place the leaf on it. Drop a few drops of iodine solution on the leaf. You will see it turn blue-black which means starch is present in the leaf.

Answer 5

Green plants contain a green plastid called cholorophyll that help in the production of starch by process of photosynthesis.

1. A peel of the green plant is dipped in hot water and rinsed in ethanol solution.

2.The peel is rinsed in hot water and kept in a dish with iodine solution.

3 The peel will appear blue/brown to show the presence of starch.

Answer 6

If the leaf tests positive for starch, it will turn blue-black when iodine solution is applied. This indicates that starch is present in the leaf. If the leaf tests negative, there will be no color change, indicating the absence of starch.

Answer 7

Iodine solution is used to test the presence of starch. we can know this as it changes its colour to blue-black.

Answer 8

The presence of starch in a leaf indicates that photosynthesis has occurred.

Answer 9

Try Potassium Iodine-Iodide (KI3) solution testing on starch will turn it blue-purple