Define a salt bridge.
A) A pathway, composed of salt water, that ions pass through.
B) A pathway in which no ions flow.
C) A pathway between the cathode and anode in which ions are reduced.
D) A pathway between the cathode and anode in which ions are oxidized.
E) A pathway by which counterions can flow between the half-cells without the solutions in the half-cell totally mixing.
Okay guys, let's take a look at the following question. So, here it says, define a salt bridge. So, let's first draw an image of what's going on inside of a galvanic cell or electrolytic cell. So, we're going to say here we have, let's say we're looking at the galvanic cell, the spontaneous one. So, we have two jars, one has one electrode the other one has another electrode, and here our salt bridge is this right here, okay? So, we have our solution and we'll see that this is metal m and this is metal n. So, metal m produces metal ions floating around in solution and metal n also has ions floating around in solution. Now, remember, we're going to say that this is a galvanic cell. So, here this is negative and this cathode here is positive, electrons naturally move from the anode to the cathode, okay? So, they're naturally moving that way. Now, what's going to happen here is the whole point of a salt bridge is to help neutralize these positive metal ions in here, because if their concentration gets too high then the left side will become more positive and the more positive that side gets the less likely electrons are to leave, okay?
Because electrons are going to want to stay where there's a opposite charge to them to counteract these positive ions from building up, that's why salt bridge is created, in this salt bridge we have neutral ions neutral negative ions like Cl minus or NO3 minus, these are neutral negative ions because they come from strong acids, in this case HCl and HNO3, because they come from strong acids they're very weak negative ions. So weak that they're neutral, meaning they're not going to take place, take part in any type of reaction. So, we don't have to fear them. So, these guys are naturally flowing from a Cathode side towards the anode side, and remember, we do this to complete the circuit, because remember, you want your electrons flowing this way and then you have negative charges, negative ions flowing the opposite way, light charges moves opposite directions close the circuit, which helps us generate electricity. So here, again, salt bridge helps to basically neutralize the anode side, get rid of all those positive ions. So, they don't build up. So, here a pathway composed of salt water that ions pass through. So, salt water is NaCl, the thing is we only have chloride ions, we don't have sodium ions, positive ions floating in there. So, this wouldn't work, here a path pathway in which no ions flow, no, we just set that chloride ion the nitrate ion flow, a pathway between the cathode and the anode in which ions are reduced, no reduction happens at the cathode, oxidation happens at the anode. So, both C and D are wrong, so the answer has to be E, a pathway by which counter ions can flow between the half cells without the solutions and the half cells totally mixing. So, yes. So ions, negative ions are formed from the cathode side to the anode side but we make sure that none of the n positive ions somehow find their way onto the m plus ion solution. So, only negative ions are flowing, none of those positive and positive ions are flowing. So, basically salt bridge helps to neutralize positive ions on the anode side from building up too much, too much of a buildup of positive ions on the anode side would stop the reaction from occurring, that side would become too positive, which means that electrons would be less likely to leave the anode and go towards the cathode. So, here option E is your answer.