Name one indicator which turns red on adding a base.

Answer

**Step-by-Step Solution:**

1. **Understanding Indicators**: Indicators are substances that change color when added to an acid or a base. They help us determine whether a solution is acidic or basic.

2. **Identifying the Indicator**: The question asks for an indicator that turns red when a base is added.

3. **Choosing the Right Indicator**: One such indicator is "Turmeric paper." Turmeric is a natural indicator that is commonly used in chemistry.

4. **Color Change Reaction**: When turmeric paper is exposed to a basic solution, it changes color from yellow to red. This color change indicates the presence of a base.

5. **Behavior in Acidic Conditions**: If turmeric paper is placed in an acidic solution, it will not change color; it will remain yellow. This property helps distinguish between acidic and basic solutions.

6. **Conclusion**: Therefore, the indicator that turns red upon adding a base is turmeric paper.

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