After the stannous chloride solution has been prepared, a few pieces of tin metal, sn, are dropped into the bottle, to prevent oxidation by air.

determine the standard cell potential for the following reaction: sn(s)+sn4+(aq)→2sn2+(aq)

express your answer with the appropriate units.

E° = 0.29 V

Explanation:

Let's consider the following redox reaction.

Sn(s) + Sn⁴⁺(aq) → 2 Sn²⁺(aq)

We can identify both half-reactions:

Reduction (cathode): Sn⁴⁺(aq) + 2 e⁻ → Sn²⁺(aq)    E°red = 0.15 V

Oxidation (anode): Sn(s) → Sn²⁺(aq)  + 2 e⁻         Ered = -0.14 V

The standard cell potential (E°) is the difference between the standard reduction potential of the cathode and the standard reduction potential of the anode.

E° = E°red, cat - E°red, an = 0.15 V - (-0.14 V) = 0.29 V

the answer is na (sodium)