Question 4
The starch test is carried out on a leaf of a plant kept in the dark for 48 hours. What is seen?
The right answer is the one marked above.
No colour change. Forty-eight hours in the dark removes the starch from the leaves completely, so there is nothing for the iodine to react with.
This is statement 2(i) of the chapter exercise, and it is false as printed there. It is also the check that the destarching worked before the real experiment begins.