Solvents

A solvent is any substance that dissolves other molecules. The substance being dissolved is called a solute. If water is used as a solvent, then the mixture is called an aqueous solution.

Water is a major component of a cell's cytoplasm, and it acts as a solvent to dissolve and deliver nutrients necessary for cell survival. Water is a polar molecule with a partial positive charge on the hydrogen atoms and a partial negative charge on oxygen; this polarity of water is essential for the chemical reactions inside the cell.

So, when table salt, sodium chloride is added to water, like most ionic compounds, it dissociates into its constituent ions.

Because water is a polar molecule, its oxygen atom is attracted to the positive sodium ions. Similarly, the hydrogen atoms are attracted to the negative chloride ions.

This creates a sphere of hydration around the sodium and chloride ions that keeps the solute particles dispersed into a homogenous mixture called a solution.