Question

Which test helps in identification of starch in the leaves?

• A. Iodine test
• B. Hydrilla test
• C. Black paper test
• D. Moll's half leaf experiment

Hint:

Iodine test result: \[ \text{Starch + Iodine} \rightarrow \text{Blue-black color} \]

Answer 1

The Correct Option is A

Concept:
Plants produce starch during photosynthesis. To identify starch in leaves, scientists use the: \[ \boxed{\text{Iodine test}} \] Iodine solution changes color in presence of starch: \[ \text{Brown iodine} \rightarrow \text{Blue-black} \] This confirms presence of starch.

Step 1: Understand starch formation in leaves.
During photosynthesis: \[ \text{Glucose is produced} \] Excess glucose gets converted into: \[ \text{Starch} \] and stored in leaves.

Step 2: Understand iodine test procedure.
Procedure:
• Boil leaf in water
• Boil in alcohol to remove chlorophyll
• Wash with warm water
• Add iodine solution Observation: \[ \text{Blue-black color appears} \] Conclusion: \[ \text{Starch is present} \]

Step 3: Analyze options carefully.
Option (A): Iodine test
Correct test for starch identification. Correct. Option (B): Hydrilla test
Used to demonstrate oxygen release during photosynthesis. Incorrect. Option (C): Black paper test
Used in photosynthesis experiments but not direct starch test. Incorrect. Option (D): Moll's half leaf experiment
Demonstrates need of carbon dioxide. Incorrect.

Step 4: Choose the correct answer.
Therefore, starch in leaves is identified using: \[ \boxed{\text{Iodine test}} \] Hence, \[ \boxed{(1)\ \text{Iodine test}} \]