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Answer the following.
The standard reduction potentials of the following electrodes are given below. Answer the questions…
The standard reduction potentials of the following electrodes are given below. Answer the questions that follow:
| Electrodes | SRP values |
|---|---|
| $\text{Fe}^{2+}/\text{Fe}$ | -0.44V |
| $\text{Mg}^{2+}/\text{Mg}$ | -2.37V |
| $\text{I}_2/2\text{I}^-$ | +0.54V |
| $\text{Ag}^+/\text{Ag}$ | +0.88V |
(a)[1.0]
Which substance/s could be used to convert iodide ions to iodine?
(b)[1.0]
From the given reactions which reaction is spontaneous and why?
I: $\text{Fe}^{2+} + 2\text{Ag} \rightarrow 2\text{Ag}^{+1} + \text{Fe}$
II: $\text{Fe}^{2+} + \text{Mg} \rightarrow \text{Mg}^{2+} + \text{Fe}$
Answer
Answer (a)
Official answer key$\mathrm{Ag^+/Ag}$
Answer (b)
Official answer keyReaction II is spontaneous as $E^\circ_{cell}$ = positive.
From ISC 2025 Practice Chemistry, question 51.