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Hydrogen Chloride

  • Page ID
    35894
  • Hydrogen chloride (HCl) is a colorless gas which forms white fumes of hydrochloric acid when brought into contact with atmospheric humidity. Inhalation of the gas can cause severe burns of the nose, throat, and upper respiratory tract (which may lead to death in severe cases). Hydrogen chloride may also result in severe burns of the eyes.

    The hydrogen and the chlorine atom are connected by a covalent single bond, which is highly polar, since the chlorine atom is much more electronegative than the hydrogen atom. Thus the molecule shows a large dipole moment with the negative charge at the chlorine atom.

    When dissolved in water, the HCl gas dissociates and forms hydronium and chloride ions:

    HCl + H2O arrow_right.gif H3O+ + Cl-

    This solution is called hydrochloric acid(1), which is a strong acid with a high acid dissociation constant.

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