Association of molecules in water is due to:

Explanation

**Step-by-Step Solution:**

1. **Understanding Water Molecule Structure**:
- A water molecule (H₂O) consists of one oxygen atom and two hydrogen atoms. The oxygen atom is more electronegative than hydrogen, which means it attracts the shared electrons more strongly.

2. **Polarity of Water Molecule**:
- Due to the difference in electronegativity between oxygen and hydrogen, the water molecule is polar. This means that the oxygen atom carries a partial negative charge (δ-) while the hydrogen atoms carry partial positive charges (δ+).

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