A student constructs a Zn|Zn^2+(1.0 M) || Cu^2+(1.0 M)|Cu galvanic cell with a KNO3 salt bridge and reads the voltage with a high-impedance voltmeter. Standard reduction potentials: Cu^2+/Cu = +0.34 V; Zn^2+/Zn = -0.76 V. The measured cell voltage at 25 C is 1.08 V.
What is the role of the KNO3 salt bridge?
- A
completes the external electron pathway
- B
provides Cu^2+ ions to the cathode
- Ccheck_circle
maintains charge neutrality by allowing ion flow between half-cells, enabling sustained current
- D
increases the cell potential beyond E^o
Explanation
The salt bridge transports K+ toward the cathode and NO3- toward the anode to balance charge as electrons flow through the wire.