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Test for Sunlight

A star-shaped...

Question

A star-shaped figure was cut in the black paper strip used for covering a part of the leaf of a destarched plant used for demonstrating that light is necessary for photosynthesis. At the end of the experiment (after the removal of chlorophyll), the leaf was tested for starch with iodine solution.

(a) What colour, if any, will be produced on the part of leaf under the star-shaped figure?
(b) Give reason for your answer.

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Solution

(a) The part of leaf under the star region will show blue black colour upon testing with iodine.
(b) The appearance of blue colour in that part indicates the presence of starch.

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