* Starch is a polysaccharide: It's a large, complex molecule made up of many sugar units linked together.

* Water is a polar solvent: It attracts and dissolves polar molecules (like sugars).

* Starch is not soluble: The large, complex structure of starch prevents it from fully dissolving in water. Instead, starch forms a suspension when mixed with water.

What happens in water:

* When you mix starch with water, the starch molecules absorb water and swell up, forming a viscous mixture called paste. This is similar to how gelatin works.

* This process is called gelatinization and is used in cooking to thicken sauces, soups, and desserts.

To truly dissolve starch, you need to use a strong acid or a base:

* These chemicals break down the complex starch molecules into smaller sugar units that can dissolve in water. This process is called hydrolysis.

* However, this method is not typically used in everyday cooking or food preparation.

So, while starch doesn't dissolve in the usual sense, it can be dispersed in water to form a paste, which has its own unique properties.