When water ionizes, it produces equal amounts of hydrogen and hydroxide ions that can reassociation with each other. The pH of water is:

Explanation:

ionic product of water Kw = 10⁻¹⁴

[H⁺] [  OH⁻ ] = 10⁻¹⁴

[H⁺] ² = 10⁻¹⁴

[H⁺] = 10⁻⁷

Water dissociates as follows .

H₂O     ⇄     H⁺      +     OH⁻

                  10⁻⁷M       10⁻⁷ M

pH = - log [H⁺]

= - log [  10⁻⁷ ]

= 7 .

So pH of pure water solution = 7 .

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