Question 3
How would you test the presence of starch in leaves?
The presence of starch in leaves can be tested using iodine test.
Procedure to test for the presence of starch in leaves:
1. Dip the leaf in boiling water for a few minutes. After this, immerse it in a beaker containing alcohol.
2. Carefully place the above beaker in a water-bath and heat till the alcohol begins to boil. This decolourises the leaf.
3. Now dip the leaf in a dilute solution of iodine for a few minutes.
4. Blue - black colouration shows the presence of starch.