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My textbook says electrolytes conduct electricity by the Movement of

  1. Dec 19, 2011 #1
    My textbook says electrolytes conduct electricity by the
    Movement of positive and negative ions. I have always thought it was due to the movement Of free electrons but it isn't so . Why is this so ? I have visited a few websites but am unable to reach an answer . By the way, when we say ionic compounds dissolve , other than dissociating , they also form bonds with water molecules right? Is this the same as reacting with water? Do thy form new ions with water molecules ?? And most importantly , how exactly do mobile ions conduct electricity in electrolytes ?? Thanks in advance !!
     
  2. jcsd
  3. Dec 19, 2011 #2

    Borek

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    Re: Electrolytes

    Generally there are no free electrons in the solution, so this option (movement of free electrons) is out of the question.

    Ions are getting solvated by water molecules - in a way you can think about solvation not as about chemical reaction, more like ordering of water dipoles just by electrostatic forces (that's not always true, but let's not confuse things further). Solvated ions float in the solution and can freely move.

    An electrical current is a movement of a charge - doesn't matter if the charge is in the form of electrons or ions. If it is charge, and it moves, you have an electric current.
     
  4. Dec 19, 2011 #3
    Re: Electrolytes

    If I understand u correctly , ur saying the valence electrons don't actually leave the shells of the ions ?
    And the solvated ions do not actually break hydrogen bonds between
    Water molecules and form hydrogen bonds with water molecules themselves ? They just remain as they are in the solution ?

    But in electricity electrons are the ones with electrical energy ? Isn't current just a conventional idea ?
     
  5. Dec 19, 2011 #4

    Borek

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    Re: Electrolytes

    Please, no textspeak at PF.

    They don't.

    Presence of ions disrupts to some extent water structure, as molecules around ions are getting ordered. To what extent depends on the solution concentration.

    No idea what you mean by "electrical energy", everything I can think of is related to charge, not electrons. Electrons happen to be charge carriers, but not the only ones. Current is a flow of an electric charge through the medium, that's a definition, not a "conventional idea".
     
  6. Dec 19, 2011 #5
    Re: Electrolytes

    Ok so even if water molecules are disrupted , no chemical reaction actually takes place ??
     
  7. Dec 19, 2011 #6
    Re: Electrolytes

    Oh and sorry for using text speak !!
     
  8. Dec 19, 2011 #7

    Borek

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    Re: Electrolytes

    That's the first approximation.

    Every ion is different and things can get complicated when you look at details, but even if there are some reactions between ions and water they don't change the way charge is transported in the solution.
     
  9. Dec 19, 2011 #8
    Re: Electrolytes

    Ok thank you !!
     
  10. Dec 19, 2011 #9
    Re: Electrolytes

    Uh by the way, this is off topic, but is molten graphite and diamond and other giant covalent structures electrical conductors ??
     
  11. Dec 19, 2011 #10
    Re: Electrolytes

    Oh and , compounds can boil right? What happens to the atoms and molecules and ions when they are boiled ?
     
  12. Dec 19, 2011 #11

    Borek

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    Re: Electrolytes

    If you have unrelated questions, please start a new thread.
     
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