Calgon is the commercial name of

Options

A. sodium hexa metaphosphate `Na_(6)P_(6)O_(18)`
B. sodium aluminium silicate `Na_(2)AlSl_(2)O_(3)`
C. Washing soda
D. `C_(17)H_(35)COONa`

Explanation

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for the commercial name of Calgon.

2. **Identifying Calgon**: Calgon is a commercial product commonly used in water treatment and as a water softener.

3. **Chemical Composition**: The main chemical component of Calgon is Sodium Hexametaphosphate.

4. **Chemical Formula**: Sodium Hexametaphosphate has the chemical formula Na6P6O18.

5. **Explanation of Sodium Hexametaphosphate**: Sodium Hexametaphosphate is a type of salt that is a polymer of metaphosphate. It is often referred to as a polymetaphosphate.

6. **Properties**: Sodium Hexametaphosphate is a white solid that is soluble in water, making it useful in various applications, including water softening.

7. **Conclusion**: Therefore, the commercial name of Calgon is Sodium Hexametaphosphate.

### Final Answer:
Calgon is the commercial name of Sodium Hexametaphosphate (Na6P6O18).

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