A sudden very fast reactions that takes place with the evolution of heat, light and large amount of gas is called an ______.

Explanation

**Step-by-Step Text Solution:**

1. **Understanding the Question**: The question describes a reaction that occurs suddenly and very quickly, producing heat, light, and a large amount of gas.

2. **Identifying the Type of Reaction**: The characteristics mentioned in the question—suddenness, rapidity, and the production of heat, light, and gas—are indicative of a specific type of chemical reaction.

3. **Defining the Reaction**: The type of reaction that fits this description is known as an "explosion." An explosion is a rapid chemical reaction that releases energy in the form of heat and light, and it often produces a large volume of gas.

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