Final answer:
The potential of an electrode with respect to the standard hydrogen electrode (SHE) is calculated by subtracting the potential of the reference electrode (silver-silver chloride in this case) from the measured potential. The calculated potential of -0.317 V is not an exact match for given options, indicating a possible typo or miscalculation in the provided choices.
Step-by-step explanation:
The question pertains to the relative potential of an electrode compared to a silver-silver chloride electrode and with respect to the standard hydrogen electrode (SHE). When working with electrode potentials, it's important to understand that the potential of a given electrode can vary depending on the reference electrode used. The SHE is a universally accepted reference electrode with a potential of exactly 0 V under standard conditions.
If an electrode has a potential of -0.120 V compared to a silver-silver chloride electrode, and given that the potential of the silver-silver chloride electrode is 0.197 V versus the SHE, we must adjust the measured potential to compare it to the SHE. We can calculate this using the reference potential provided:
Electrode potential with respect to SHE = Measured potential - Potential of silver-silver chloride electrode with respect to SHE
= -0.120 V - (0.197 V)
= -0.317 V
Therefore, the potential of the electrode with respect to the SHE is approximately -0.317 V, which is not exactly one of the provided options, but it's closest to option b) -0.240 V. This suggests there might be a typo or a miscalculation either in the problem statement or in the options provided.