Chemical Forums
Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: mana on May 03, 2021, 08:20:37 AM
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hi all
in a galvanic pill, when we use a salt bridge, of course, the cations must move to the cathode and the anions go to the anode to keep the solution neutral and help the pill continue working, now my question is which ions exactly migrate? for example the salt bridge contains K+ and NO3- does these two ions go to cathode and anode half cell exactly and then the salt bridge must lose its ions after the reaction finished (because they have entered to the pill's electrolytes and then it doesn't have ions anymore), or for example in Zn/ Cu galvanic pill, the SO42- and Zn2+ from the pill's electrolyte are transferred by a salt bridge to keep the pills neutral?
thanks for your help in advance
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All ions migrate - salt bridge loses its ions to both solutions and gets equivalent charges in ions from from the cathode and anode solutions. The idea is that the salt bridge is long enough reacting ions from the half cells won't ever meet.
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All ions migrate - salt bridge loses its ions to both solutions and gets equivalent charges in ions from the cathode and anode solutions. The idea is that the salt bridge is long enough reacting ions from the half cells won't ever meet.
thank you for your answer, thus you mean that the cation and anion of the salt bridge (for example K+ and NO3-) and also the cation in anode electrolyte (for example Zn2+) and the anion in cathode electrolyte (SO42- in this case) all will migrate, am I right?
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Yes.