[confusedstud]

In a electrolysis setup with two platinum electrodes, at the anode the electrolyte is aqueous hydrochloric acid 1 mol/dm^3 and at the cathode the electrolyte is aqueous sodium bromide 1mol/dm^3. In between the two there is a salt bridge present to blance the charge difference. At the anode and cathode's electrolyte will the pH change?

For such a case, is 1mol/dm3 considered to be concentrate since the HCl might let Cl- oxidise rather than the OH-. Usually how many moles per dm3 of the halide ions wil then be considered as concentrated?
Also, if it is considered to be dilute, then will the pH at the anode change? Since OH- ions are driven away then anions from the salt bridge will come down to balance the charge. In most cases the salt bridge contains KNO3, so will nitrate ions come down or will hydroxide ions come down from the bridge? Lastly, at the cathode hydrogen will be reduced, so will potassium ions come down or will hydrogen ions? Because if hydrogen/hydroxide ions were to come down rather than potassium and nitrate, then the pH will remain the same but if nitrate and potassium ions were to come down then the pH of will increase/decrease at the individual electrolytes.

Thanks!

[Arkcon]

Start here:  http://www.chemicalforums.com/index.php?topic=59251.0

[confusedstud]

Hi Arkcon I saw the animation but which ions are given out from the salt bridge? Are they the eg Potassium ion and nitrate ion or is it the H+ ion or OH- ions? Thanks for the *delete me*

[Arkcon]

Like the responses in that post says ... yes, the potassium and nitrate ions do migrate out of the salt bridge to conduct the current.