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Guilherme Mazui

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What is the Difference Between Hydronium Ion and Hydrogen Ion?

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The difference between hydronium ions and hydrogen ions lies in their structure and stability.

  • Hydrogen Ion (H+): A hydrogen ion is simply a proton, obtained by removing an electron from a hydrogen atom. It is highly reactive and cannot exist in aqueous solutions without combining with water.
  • Hydronium Ion (H₃O+): A hydronium ion is formed when a hydrogen ion (H+) combines with a water molecule (H₂O) and becomes attracted to the negative pole of a hydroxide ion (OH-). It is a positively charged molecule that consists of one oxygen atom and three hydrogen atoms.

Some key points to remember are:

  • Hydronium ions are stable compared to hydrogen ions.
  • Hydronium ions are generated by protonation of water.
  • Hydronium ions are present in acidic solutions, and their concentration directly relates to the pH of the solution.

In summary, while hydrogen ions (H+) exist as protons, hydronium ions (H₃O+) are formed when hydrogen ions bind to water molecules, making them more stable. The two ions have different structures and play different roles in aqueous solutions.

On this page
  • What is the Difference Between Hydronium Ion and Hydrogen Ion?
  • Comparative Table: Hydronium Ion vs Hydrogen Ion

    • Comparative Table: Hydronium Ion vs Hydrogen Ion

    Here is a table summarizing the differences between hydronium ions and hydrogen ions:

    Feature Hydrogen Ion (H+) Hydronium Ion (H3O+)
    Symbol H+ H3O+
    Formation Obtained by removing an electron from a hydrogen atom Formed when a hydrogen ion (proton) combines with a water molecule
    Reactivity Highly reactive, leading to its immediate combination with water in aqueous solutions Stable in aqueous solutions, does not readily react with other molecules
    Structure Lone proton Water molecule with an extra proton, trigonal pyramidal geometry, composed of three hydrogen atoms and one oxygen atom
    pH Scale Hydrogen ions are responsible for acidity, and their concentration is used to calculate pH values Hydronium ions do not directly affect pH values, but their concentration can be used to determine the pH of a solution indirectly

    In summary, the key difference between a hydronium ion and a hydrogen ion is that a hydronium ion is a water molecule with an extra proton, while a hydrogen ion is a lone proton.

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    Guilherme Mazui

    Guilherme Mazui is graduated in journalism from the Federal University of Minas Gerais (UFMG) and a master's degree in Communication from the University of São Paulo (USP). In addition, he has experience in advertising writing and has worked as a content editor in several companies.