The reaction in which the same substance undergoes oxidation as well as reduction is called `"…..................."` reaction.

Answer

To solve the question, we need to identify the term that describes a specific type of chemical reaction. Here’s the step-by-step solution:

### Step 1: Understand the Definitions
- **Oxidation**: This is the process where a substance loses electrons.
- **Reduction**: This is the process where a substance gains electrons.

### Step 2: Identify the Type of Reaction
- A reaction where the same substance undergoes both oxidation and reduction means that it is both losing and gaining electrons simultaneously.

### Step 3: Recall the Term
- The specific term used to describe this type of reaction is "disproportionation reaction." In a disproportionation reaction, a single substance is transformed into two different products, one of which is oxidized and the other is reduced.

### Final Answer
The reaction in which the same substance undergoes oxidation as well as reduction is called a **disproportionation reaction**.

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