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Redox and electrode potentials

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Question 15

The redox equilibria for a rechargeable nickel–cadmium cell during discharge are based on the standard electrode potentials below:

Cd(OH)2(s)+2e−⇌Cd(s)+2OH−(aq)Eθ=−0.80 V \text{Cd(OH)}_2(\text{s}) + 2\text{e}^- \rightleftharpoons \text{Cd}(\text{s}) + 2\text{OH}^-(\text{aq}) \quad E^\theta = -0.80\text{ V} Cd(OH)2​(s)+2e−⇌Cd(s)+2OH−(aq)Eθ=−0.80 V NiO(OH)(s)+H2O(l)+e−⇌Ni(OH)2(s)+OH−(aq)Eθ=+0.49 V \text{NiO(OH)}(\text{s}) + \text{H}_2\text{O}(\text{l}) + \text{e}^- \rightleftharpoons \text{Ni(OH)}_2(\text{s}) + \text{OH}^-(\text{aq}) \quad E^\theta = +0.49\text{ V} NiO(OH)(s)+H2​O(l)+e−⇌Ni(OH)2​(s)+OH−(aq)Eθ=+0.49 V

What is the overall equation for the cell reaction during discharge?

2NiO(OH)(s)+Cd(s)+2H2O(l)→2Ni(OH)2(s)+Cd(OH)2(s) 2\text{NiO(OH)}(\text{s}) + \text{Cd}(\text{s}) + 2\text{H}_2\text{O}(\text{l}) \rightarrow 2\text{Ni(OH)}_2(\text{s}) + \text{Cd(OH)}_2(\text{s}) 2NiO(OH)(s)+Cd(s)+2H2​O(l)→2Ni(OH)2​(s)+Cd(OH)2​(s)
2Ni(OH)2(s)+Cd(OH)2(s)→2NiO(OH)(s)+Cd(s)+2H2O(l) 2\text{Ni(OH)}_2(\text{s}) + \text{Cd(OH)}_2(\text{s}) \rightarrow 2\text{NiO(OH)}(\text{s}) + \text{Cd}(\text{s}) + 2\text{H}_2\text{O}(\text{l}) 2Ni(OH)2​(s)+Cd(OH)2​(s)→2NiO(OH)(s)+Cd(s)+2H2​O(l)
NiO(OH)(s)+Cd(s)+H2O(l)+OH−(aq)→Ni(OH)2(s)+Cd(OH)2(s) \text{NiO(OH)}(\text{s}) + \text{Cd}(\text{s}) + \text{H}_2\text{O}(\text{l}) + \text{OH}^-(\text{aq}) \rightarrow \text{Ni(OH)}_2(\text{s}) + \text{Cd(OH)}_2(\text{s}) NiO(OH)(s)+Cd(s)+H2​O(l)+OH−(aq)→Ni(OH)2​(s)+Cd(OH)2​(s)
2NiO(OH)(s)+Cd(s)→2Ni(OH)2(s)+Cd(OH)2(s) 2\text{NiO(OH)}(\text{s}) + \text{Cd}(\text{s}) \rightarrow 2\text{Ni(OH)}_2(\text{s}) + \text{Cd(OH)}_2(\text{s}) 2NiO(OH)(s)+Cd(s)→2Ni(OH)2​(s)+Cd(OH)2​(s)

Redox and electrode potentials Questions

  1. A Level
  2. /Chemistry
  3. /Redox and electrode potentials