Dissociation in Water
Water is a polar molecule. If we represent water using Lewis structures we will get the following:
You will notice that there are two electron pairs that do not take part in bonding. This side of the water molecule has a higher electron density than the other side where the hydrogen atoms are bonded. This side of the water molecule is more negative than the side where the hydrogen atoms are bonded.
We say this side is the delta negative (\(\delta -\)) side and the hydrogen side is the delta positive (\(\delta +\)) side. This means that one part of the molecule has a slightly positive charge (positive pole) and the other part has a slightly negative charge (negative pole). We say such a molecule is a dipole. It has two poles. The figure below shows this.