What substance has a pH of 7, meaning it is neutral?

Water is a substance that has a pH of 7, indicating that it is considered neutral on the pH scale. The pH scale ranges from 0 to 14, where values below 7 represent acidity and values above 7 represent alkalinity. A pH of 7 signifies that the concentrations of hydrogen ions (H⁺) and hydroxide ions (OH⁻) are equal, resulting in a neutral solution.

In contrast, substances like blood and saline have a slightly alkaline pH (around 7.35 to 7.45 for blood and typically around 7.4 for saline), while vinegar is acidic, generally having a pH around 2 to 3 due to the presence of acetic acid. Understanding the pH of substances is crucial in biological processes, as many physiological functions depend on maintaining the appropriate pH levels.