Water is ionized through the addition of minerals which subsequently gain or lose electrons, or through the self-ionization of water molecules themselves.
Here's a breakdown:
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Mineral Ionization: Naturally occurring water sources, such as rivers and streams, contain dissolved minerals. When these minerals (like calcium, magnesium, or bicarbonate) dissolve in water, they dissociate into ions, meaning they gain or lose electrons and become charged particles. This process contributes to the ionization of water.
- For example, calcium carbonate (CaCO3) from limestone can dissolve into calcium ions (Ca2+) and carbonate ions (CO32-).
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Self-Ionization of Water: Even pure water undergoes a slight degree of self-ionization. A water molecule (H2O) can act as both an acid and a base, donating a proton (H+) to another water molecule. This forms a hydronium ion (H3O+) and a hydroxide ion (OH-). This process is described by the following equilibrium:
2H2O ⇌ H3O+ + OH-
While the extent of self-ionization is small at room temperature, it's a fundamental aspect of water's chemical properties.
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Electrolysis: Another method to ionize water is through electrolysis. When an electric current is passed through water, it decomposes into hydrogen ions (H+) and hydroxide ions (OH-) at the electrodes, which then react to form hydrogen gas (H2) and oxygen gas (O2), respectively.
In summary, water ionization occurs either through the dissolving of minerals which then ionize, the self-ionization process of water molecules, or through the application of an electric current (electrolysis).
