Water Is Full of Holes

Water is known as a Universal Solvent, because it dissolves most everything. It can do this because water is full of holes.


Some Liquids have Structure
There are simplistically speaking, two kinds of liquids:

- Unstructured liquids have their molecules held together by relatively weak non-directional Van Del Waals forces. These molecules fill space fairly well. Liquid detergents are an example of a widely used unstructured liquid.

Unstructured Liquid
Source - sites.bergen.org

Structured Liquid
Source - ifm.liu.se

- Structured liquids have their molecules held together by relatively stronger forces that exhibit an orientation or direction (polarity) as hydrogen bonds do in water. These molecules do not fill space well - there are voids throughout these liquids that other materials can fill very well.


Water, a Structured Liquid, has Voids
As is obvious from the illustrations, unstructured liquids have very few voids, while structured liquids have voids. The more (and larger voids) a liquid has, the more molecules (and kinds of molecules) of other materials the liquid can absorb i.e. the more universally solvent the liquid is. 
A large part of the volume of liquid water is made up of voids


Water has voids because of Hydrogen Bonds

Source - science.csustan.edu

Hydrogen bonds, it is assumed, shown as grey lines between the water molecules, create the voids in water. The  water molecule,  which  contains two  hydrogen atoms  and  one  oxygen atom  in  a  nonlinear arrangement, is ideally  suited  to  engage  in  hydrogen bonding