Water is known as the universal solvent because it has the ability to dissolve many substances. This unique property of water makes it an essential component for various processes in nature and in our daily lives. Let's explore why water is called the universal solvent in detail:

1. Definition of a solvent:
- A solvent is a substance that has the ability to dissolve other substances, known as solutes, to form a homogeneous mixture called a solution.
- Solvents can dissolve solutes by breaking the bonds between their particles, allowing the solute particles to spread evenly throughout the solvent.

2. Water's molecular structure:
- Water is a polar molecule, meaning it has a slightly positive charge at one end (hydrogen atoms) and a slightly negative charge at the other end (oxygen atom).
- This polarity arises due to the unequal sharing of electrons between hydrogen and oxygen atoms.
- The polarity of water molecules allows them to interact with other polar and ionic substances, making water an excellent solvent.

3. Dissolving process:
- When a solute is added to water, the positive end of the water molecule attracts the negative ions of the solute, while the negative end attracts the positive ions.
- These attractions weaken the bonds between the solute particles, causing them to separate and disperse in the water.
- The solute particles become surrounded by water molecules, forming a hydration shell, which prevents them from recombining.

4. Versatility of water as a solvent:
- Water can dissolve a wide range of substances, including salts, sugars, gases, acids, and many organic compounds.
- Salts and ionic compounds dissolve in water due to the attraction between the polar water molecules and the charged ions.
- Polar substances, such as sugars and alcohols, dissolve easily in water because they can form hydrogen bonds with water molecules.
- Nonpolar substances, such as oils and fats, do not dissolve in water because they lack a charge and cannot form hydrogen bonds.

5. Importance of water as a universal solvent:
- Water's ability to dissolve substances is crucial for various biological processes, such as digestion, respiration, and transportation of nutrients in living organisms.
- In nature, water acts as a solvent in weathering rocks, transporting minerals, and facilitating chemical reactions.
- In our daily lives, water is used as a solvent in cleaning, cooking, and manufacturing processes.

In conclusion, water is called the universal solvent because of its ability to dissolve a wide range of substances due to its polarity and hydrogen bonding. This property makes water an essential component for many natural and human-made processes.