Pure water, also known as distilled or deionized water, is water that has been filtered or processed to remove impurities and contaminants. Here are some key characteristics and uses of pure water:

Characteristics

1. Chemical Composition: Pure water is composed of two hydrogen atoms and one oxygen atom (H₂O).
2. pH Level: It has a neutral pH of 7 at 25°C (77°F).
3. Conductivity: Pure water has very low electrical conductivity because it lacks ions.
4. Appearance: It is clear, colorless, and odorless.
5. Boiling and Freezing Points: It boils at 100°C (212°F) and freezes at 0°C (32°F) at standard atmospheric pressure.

Uses

1. Laboratory Work: Used in experiments and procedures that require uncontaminated water.
2. Medical Applications: Used in sterilization processes and for preparing medications.
3. Industrial Processes: Used in manufacturing and cleaning processes where impurities could affect product quality.
4. Aquariums: Often used to maintain water quality and prevent contamination.
5. Beverages: Used in the preparation of certain beverages to ensure purity and taste.

Methods of Purification

1. Distillation: Involves boiling water and then condensing the steam back into a liquid, leaving impurities behind.
2. Deionization: Removes mineral ions (such as sodium, calcium, iron, and copper) using ion exchange resins.
3. Reverse Osmosis: Forces water through a semipermeable membrane to remove impurities.
4. Filtration: Uses activated carbon or other filters to remove contaminants.

Pure water is essential in various applications where the presence of impurities could be detrimental. Its production and use are crucial in scientific, medical, and industrial fields.