Some crushed boil rice, water and saliva mixture is warmed in a test-tube for about 15 to 20 minutes and 2 or 3 drops of dilute iodine solution are added to it. The colour produced will be :

Options

A. violet
B. green
C. blue-black
D. none of these

Answer

To solve the question about the color produced when crushed boiled rice, water, and saliva mixture is warmed and then treated with iodine solution, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Components**:
- The mixture consists of crushed boiled rice, water, and saliva.
- Boiled rice contains starch, which is a carbohydrate.

2. **Role of Saliva**:
- Saliva contains the enzyme amylase, which is responsible for breaking down starch into simpler sugars.

3. **Heating the Mixture**:
- When the mixture is warmed for 15-20 minutes, the amylase enzyme in the saliva will begin to digest the starch present in the boiled rice.

4. **Adding Iodine Solution**:
- Iodine solution is typically yellow in color and is used to test for the presence of starch.
- When iodine reacts with starch, it produces a blue-black color.

5. **Analyzing the Reaction**:
- Since the amylase enzyme has broken down the starch in the rice, there will be little to no starch left in the mixture when iodine is added.
- Therefore, there will be no reaction between iodine and starch.

6. **Conclusion**:
- As there is no starch present to react with the iodine, the color of the solution will remain unchanged.
- The final answer is that the color produced will be "none of these."

### Final Answer:
None of these.

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