Salt Bridge (1 Viewer)

[HeroicPandas]

The salt bridge in the galvanic is cell is used for the migration of ions between half-cells for neutralisation of excess charge

Say we have a galvanic cell: Mg(s) | Mg2+ || Cu(s) | Cu2+ (where magnesium the anode and copper is the cathode)

As time progresses, magnesium is oxidised into magnesium ions, this will make the anolyte more 'positive'. To neutralise charge for efficient electron transfer, anions are moved into the anode compartment

Here is the question: how do the anions move into the anoylte? Yes i know its through the salt bridge, or the anions from the salt bridge move into the anolyte, but HOW? Do the ions have brains? Or does the excess positive charge ATTRACT the negative charges causing anions to go into the anolyte? (like a strong big positive magnet attracting a weak small negative magnet)

Anolyte - electrolyte in the anode compartment, oxidation half-cell

 

[ocatal]

According to my textbook, magnesium ions would move into the salt bridge and 'push' potassium ions (from the KNO₃ solution) into the cathode, effectively neutralising the imbalance of charge.

In that case, I would assume copper ions would do the same with nitrate ions.

 

[ashbash4210]

Basically, its just like you said, the excess positive charge of the anolyte attracts the anions in the saltbridge, for example if KNO3 was used, the nitrate ions would be attracted to the anolyte and move into the solution, thus nuetralising the excess charge caused by the oxidation reaction, with a similar action taking part in the cathode half cell. However, for the course you dont need to know the specific details of it, in all the past questions ive done all you need to know about the salt bridge is that it completes the circuit by allowing anions and cations to move.

 

[HeroicPandas]

According to my textbook, magnesium ions would move into the salt bridge and 'push' potassium ions (from the KNO₃ solution) into the cathode, effectively neutralising the imbalance of charge.

In that case, I would assume copper ions would do the same with nitrate ions.

Ah they 'push' it out...thanks! I remember looking at solutions for some paper and they said that the IONS actually move from half-cell to half-cell...lol, if i can find it, i'll post it up (i think the question is in the chem marathon)

Basically, its just like you said, the excess positive charge of the anolyte attracts the anions in the saltbridge, for example if KNO3 was used, the nitrate ions would be attracted to the anolyte and move into the solution, thus nuetralising the excess charge caused by the oxidation reaction, with a similar action taking part in the cathode half cell. However, for the course you dont need to know the specific details of it, in all the past questions ive done all you need to know about the salt bridge is that it completes the circuit by allowing anions and cations to move.

ahh ok, thank you!