Water dissolves sugar because of the unique properties of both water and sugar molecules.

Water is a polar molecule, meaning that it has a positive charge at one end and a negative charge at the other. This polarity is due to the uneven distribution of electrons in the molecule, with the oxygen atom having a higher electron density than the hydrogen atoms. This gives the oxygen atom a partial negative charge, while the hydrogen atoms have partial positive charges.

Sugar, on the other hand, is a nonpolar molecule. It is made up of carbon, hydrogen, and oxygen atoms, but the distribution of electrons within the molecule is more evenly balanced, resulting in a lack of polarity.

Despite their differences in polarity, water and sugar are able to interact due to the properties of the water molecule. The oxygen atom in water has a strong affinity for electrons, which allows it to form hydrogen bonds with other molecules. These hydrogen bonds are weaker than covalent bonds, but they are numerous and important in determining the properties of water.

When sugar is placed in water, the water molecules are attracted to the sugar molecules due to the partial charges on the oxygen and hydrogen atoms. The water molecules form hydrogen bonds with the sugar molecules, pulling them into the water. This process is known as solvation, and it allows sugar to dissolve in water.

The ability of water to dissolve sugar is important for many biological processes. In the human body, for example, water helps to transport nutrients and waste products through the bloodstream by dissolving them. Similarly, water is able to dissolve many other substances, including salts, acids, and bases, making it a universal solvent.

In summary, water dissolves sugar due to the polarity of the water molecule and the ability of the oxygen atom to form hydrogen bonds with other molecules. This process, known as solvation, allows water to dissolve many substances and is important for many biological processes.