Given below are the steps to be followed for performing 'starch test' on a green leaf.
(A) Boil the leaf in alcohol (B) Boil the leaf in water
`(C)`Dip the leaf in iodine solution (D) Wash the leaf in water
Which one of the following sequences should the students follow to get the correct result?

Options

A. `(A),(D),(B),(C)`
B. `(D),(A),(B),(C)`
C. `(B),(D),(A),(C)`
D. `(B),(A),(D),(C)`

Answer

To perform the starch test on a green leaf, the correct sequence of steps is as follows:

1. **Boil the leaf in water (Step B)**: This step is essential to soften the leaf and remove any chlorophyll, which allows for better penetration of the iodine solution later. Boiling in water helps to break down the cell walls and prepare the leaf for the next steps.

2. **Boil the leaf in alcohol (Step A)**: After boiling in water, the leaf is then boiled in alcohol. This step is crucial as it removes the chlorophyll and any other pigments, making it easier to see the color change when iodine is added.

3. **Wash the leaf in water (Step D)**: After boiling in alcohol, the leaf should be washed in water. This step helps to remove any excess alcohol and prepares the leaf for the iodine solution.

4. **Dip the leaf in iodine solution (Step C)**: Finally, the leaf is dipped in iodine solution. If starch is present in the leaf, it will turn blue-black, indicating a positive result for the starch test.

So, the correct sequence is: **B → A → D → C**.