because the leaf doesnot contain starch in it
It change from orange/brown colour to blue/black if starch is present
The starch solution will turn black, while the distilled water will remain brown, the same colour as the iodine. This is actually because water, normally used as a control, does not contain any starch and as we know, the iodine test is highly specific for the presence of starch hence no colour change other than iodine dissolving in water to form an iodine solution contrary to starch which we know complexes with iodine, to form starch-iodine complex forming the blue-black colour observed
The color of solid iodine is a dark purple.
Iodine
There is a dark blue colour when iodine is added to starch instead of a yellow sort of colour when iodine is added to a substance without starch.
Iodine
I stands for iodine. It is placed in group-17.
it is a yellowish/orange colour but when iodine is present, than it will turn an dark-blue/black colour
They are usd b'cos the dyes have positive electrons which react with the negative in the specimens therby giving them colour or no colour 2 be observed & identified.
The colour of the iodine will turn from yellowish brown to dark blue
cause iodine(brown) stains the rice
explain why the iodine test gave such results upon prolonged heating