1. Polarity:
* Water molecules have a bent shape with oxygen being more electronegative than hydrogen. This creates a partial negative charge on the oxygen atom and partial positive charges on the hydrogen atoms.
* Polar molecules also have uneven charge distribution, with one end having a partial positive charge and the other end a partial negative charge.
2. Hydrogen Bonds:
* The partial positive hydrogen atoms of one water molecule are attracted to the partial negative oxygen atom of another water molecule, forming hydrogen bonds.
* These strong bonds create a cohesive network of water molecules.
3. Breaking Up Polar Molecules:
* When a polar molecule enters water, the water molecules surround it and form hydrogen bonds with the polar ends of the molecule.
* The strong attraction of water molecules to the polar molecule disrupts the interactions between the polar molecule's own components, essentially pulling it apart.
* This process is called solvation or hydration.
Example:
* Table salt (NaCl) is a polar molecule. When dissolved in water, the water molecules surround the sodium and chloride ions.
* The partial negative oxygen atoms of water are attracted to the positively charged sodium ions, and the partial positive hydrogen atoms of water are attracted to the negatively charged chloride ions.
* This disrupts the ionic bonds holding the sodium and chloride ions together, allowing them to separate and dissolve in water.
In summary: Water's strong polarity and ability to form hydrogen bonds allow it to effectively break up other polar molecules by attracting them and disrupting their internal interactions. This is why water is often called the "universal solvent" for polar substances.
