No chemical reaction takes place when granules of a solid, A, are mixed with the powder of another solid, B. However when the mixture is heated, a reaction takes place between its components. One of the products, C, is a metal and settles down in the molten state while the other product, D floats over it. It was observed that the reaction is highly exothermic.
Mention any two types of reaction under which above chemical reaction can be classified.

Explanation

To classify the chemical reaction described in the question, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Reaction**:
- We start with two solids, A and B, which do not react at room temperature. This indicates that they are stable and do not undergo any chemical change until a certain condition (heating) is applied.

2. **Heating the Mixture**:
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