Why is pure water neutral?
I think its because its neither acidic nor alkaline hence it has a PH of exactly 7 due to the presence of both H+ and OH- ions.
Pure water is neutral because it doesn't contain any contamonation just like ions like impure water contains some ions like chloride sulphates, etc.
Contamination talks about the purity. Neutrality is based on PH isnt it?
I would not accept either answer although the response that pH talks about neutrality and contamination talks about purity. But the reason why H2O is neutral is that (H^+) = (OH^-) and FOR THAT REASON, the pH=7.0. You are correct that pure water is neither acidic nor alkaline and that is because (H^+) and (OH^-) are equal.
Isn't water the only compound that contains H+ and OH-. An acid only contains H+ and an alkali would contain OH-. Therefore isn't the presence of both ions H+ and OH- ions enough to say it is neutral?
You are correct! Pure water is neutral because it has a pH of 7, which means it is neither acidic nor alkaline. The reason for this neutrality is the presence of both hydrogen ions (H+) and hydroxide ions (OH-) in equal amounts.
To understand why pure water has a pH of 7, you need to know about the concept of pH and the self-ionization of water. pH is a scale that measures the acidity or alkalinity of a solution. It ranges from 0 to 14, where 0 is highly acidic, 7 is neutral, and 14 is highly alkaline. The pH scale is based on the concentration of hydrogen ions (H+) in a solution.
Water molecules can undergo a process called self-ionization, where a small fraction of water molecules break apart into hydrogen ions (H+) and hydroxide ions (OH-). This process is represented by the equation:
H2O ⇌ H+ + OH-
In pure water, this self-ionization occurs equally in both directions. As a result, the concentration of hydrogen ions (H+) is equal to the concentration of hydroxide ions (OH-), making the solution neutral. Consequently, the pH of pure water is 7, indicating the balanced presence of both acidic and alkaline components.
To determine the pH, you can use a pH indicator or measure the concentration of hydrogen ions using a pH meter. However, it's important to note that the pH of water can change if it comes into contact with substances that can donate or accept ions, such as acids or bases.