- Neutrality of a solution is determined by having an equal number of moles of H+ and OH– ions
- It is often considered that a pH of 7 is neutral – however this is incorrect for several reasons:
- pH represents the concentration of H+ ions:
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- pH of 7.0 equates to H+ ions at a concentration of 10−7 mol/L
- However, a solution of hydrogen ions alone at this concentration without OH– would clearly not be neutral
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- pH changes with temperature, as does the pH of neutrality
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- Neutral being represented by a pH of 7.0 is only correct for a specific situation – distilled water at standard temperature and pressure
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- pH represents the concentration of H+ ions:
