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What will happen to the boiling leaf when in ethanol what will happen to the leaf and the ethanol?
the ethanol will change colour and the leaf will soften
What is the texture of a leaf before boiling it in ethanol?
what type of leaf?
What happens when you soak green leaves in ethanol?
Ethanol extracts chlorophyll from leaf .
Why does ethanol turn a leaf white?
it breaks down the chlorophyll
Why does leaf turn light green when boiled in ethanol?
add the leaf to boiling ethanol in a water bath for a few minutes (the boiling ethanol dissolves the chlorophyll and removes the green colour from the leaf - it turns white so it is easy to see the change in colour) wash with water to rehydrate and soften the leaf
Why did the leaf turn brittle in testing a leaf for starch?
The leaf turns brittle during the testing the leaf for starch because the ethanol extracts the all water content from the leaf.
When testing a leaf for starch why is it rinsed in cold water after it is boiled?
After the leaf has been placed in ethanol it becomes very brittle. It is then rinsed in cold water so as to soften it and makes it more manageable for the addition of iodine.
How do you carry out to test for presence of starch?
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 a 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 in the boiling water for ten seconds or so. Then add to the ethanol, and allow to boil for about a minute until all the color 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 color indicates starch is present.
Why does leaf turn blue black when boiled in ethanol first then iodine?
Boiling in ethanol strips the leaf's waxy outer coating off, then the iodine turns it blue black because it's reacting to the presence of starch, a product of photosynthesis.
When a leaf becomes crispy after being boiled in ethanol how do you remove it?
by immersing it in a hot water bath
What is the result of the Test for the presence of starch in a leaf?
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.
Why did leaf had to be boiled in ethanol when testing leaf for starch?
Ethanol dissolves chlorophyll hence further phtosynthetic activity is stopped in the abscence of light and the leaf becomes transparent (colorless). the colorless leaf takes better stain with iodene while testing for the presence of starch.
