A voltaic cell employs the following redox reaction: Sn2+(aq)+Mn(s)→Sn(s)+Mn2+(aq)?

2015-09-01 7:16 am

Calculate the cell potential at 25 ∘C under each of the following conditions.
A. Standard
B. [Sn2+]= 1.32×10−2 M ; [Mn2+]= 1.93 M
C. [Sn2+]= 1.93 M ; [Mn2+]= 1.32×10−2 M

回答 (1)

戇戇居士

2015-09-01 7:47 am

✔ 最佳答案

A.
Reduction potentials :
Sn²⁺(aq) + 2e⁻(aq) → Sn(s) .... E° = -0.14 V
Mn²⁺(aq) + 2e⁻(aq) → Mn(s) .... E° = -1.18 V

Standard cell potential, ΔE°
= [(-0.14) - (1.18)] V
= +1.04 V

B.
cell potential, ΔE
= ΔE° - (RT / 2F) ln ([Mn²⁺] / [Sn²⁺])
= +1.04 - [8.314 × (273 + 25) / (2 × 96500)] ln[1.93 / (1.32 × 10⁻²)] V
= +0.98 V

C.
cell potential, ΔE
= ΔE° - (RT / 2F) ln ([Mn²⁺] / [Sn²⁺])
= +1.04 - [8.314 × (273 + 25) / (2 × 96500)] ln[(1.32 × 10⁻²) / 1.93] V
= +1.10 V

👍 7 👎 0