Which of the following process is responsible for the formation of delta at a place where rivers meet the sea?

Options

A. Emulsification
B. Colloid formation
C. Coagulation
D. peptisation

Explanation

To determine which process is responsible for the formation of a delta at the point where rivers meet the sea, we need to analyze the provided options: emulsification, colloid formation, coagulation, and peptization.

### Step-by-Step Solution:

1. **Understanding Delta Formation**:
- A delta is formed at the mouth of a river where it meets a larger body of water, such as a sea or ocean. This process involves the deposition of sediments carried by the river.

2. **Analyzing the Options**:
- **Emulsification**: This process involves the breakdown of larger fat globules into smaller ones and is related to the formation of emulsions (liquid in liquid). Since a delta is not an emulsion, this option is not applicable.
- **Colloid Formation**: This refers to the creation of a colloidal solution. While river water can contain colloidal particles, the formation of a delta is not due to the mere formation of colloids, making this option incorrect.
- **Coagulation**: This is the process where colloidal particles aggregate and settle out of a solution. When river water, which contains colloidal clay, meets seawater rich in electrolytes, coagulation occurs. The electrolytes cause the colloidal particles in the river water to aggregate and settle, leading to the formation of a delta.
- **Peptization**: This is the process of converting a precipitate into a colloidal solution, usually in the presence of a peptizing agent. This process does not relate to delta formation and is therefore not relevant.

3. **Conclusion**:
- The correct answer is **coagulation**. When river water (a colloidal solution of clay) meets seawater (rich in electrolytes), the electrolytes cause the colloidal particles to coagulate and settle, forming a delta.

### Final Answer:
The process responsible for the formation of a delta at a place where rivers meet the sea is **coagulation** (Option 3).

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