What is the role of builder in synthetic detergents ?

Explanation

**Step-by-Step Solution:**

1. **Definition of Builders in Synthetic Detergents:**
Builders are substances added to synthetic detergents to enhance their cleaning efficiency. They play a crucial role in water softening.

2. **Role of Builders:**
The primary function of builders is to bind with cations, specifically calcium (Ca²⁺) and magnesium (Mg²⁺) ions, which are responsible for water hardness.

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