Here's why:
* pH scale: The pH scale measures the acidity or alkalinity of a solution. It ranges from 0 to 14.
* Neutral pH: A pH of 7 is considered neutral. This means the solution has an equal concentration of hydrogen ions (H+) and hydroxide ions (OH-).
* Pure water: Pure water contains a very small amount of H+ and OH- ions due to the autoionization of water molecules. This autoionization results in a balanced concentration of both ions, leading to a neutral pH of 7.
However, it's important to note that:
* Temperature affects pH: The pH of pure water can vary slightly depending on the temperature. At higher temperatures, the ionization of water increases, resulting in a slightly lower pH (closer to 6.5).
* Dissolved impurities: Real-world water is rarely perfectly pure. Even small amounts of impurities (like dissolved minerals or gases) can affect the pH.
