1. Write reduction half reaction and the oxidation half reaction.
2. Write the balanced redox equation.
3. Calculate the cell potential, E°. Show your work.
4. Indicate whether the reaction is spontaneous or nonspontaneous.

Write reduction half reaction and the oxidation half reaction.

Rb → Rb+ + e-   E = +2.92 ------> reduction

Ag → Ag + e-   E = -0.8 ------> oxidation

Write the balanced redox equation.

Rb+  +  Ag → Ag+  +  Rb

Calculate the cell potential, E°. Show your work.

E° = E reduction + E oxidation

E° = (+2.92) + (-0.8)

E° = 2.12

Indicate whether the reaction is spontaneous or nonspontaneous.

If E° is positive which means ΔG is negative and the reaction will be spontaneous.
If E° is negative which means ΔG is positive and the reaction will be non spontaneous.

Since E° is positive in this case the reaction is spontaneous.