Question

1. what is polarity? what about a water molecule makes it a polar molecule?

Explanation:

Polarity refers to the separation of electric charge leading to a molecule having an electric - dipole moment with a negatively charged end and a positively charged end. In a water molecule ($H_2O$), oxygen is more electronegative than hydrogen. Oxygen pulls the shared electrons more strongly towards itself, creating a partial negative charge ($\delta -$) on the oxygen atom and partial positive charges ($\delta +$) on the hydrogen atoms. The bent molecular geometry of water also contributes to the overall dipole moment, making it a polar molecule.

Answer:

Polarity is the separation of electric charge in a molecule creating a dipole moment. In a water molecule, oxygen's high electronegativity and the bent molecular geometry make it polar.