Question

Write net equation for the spontaneous redox reaction and determine the standard cell potential that results when each of the following redox couples are connected in an electrochemical cell.

Instructions:

• Enter all substances in the order listed at the top of the column.
• Use a carot to indicate a superscript, but do nothing for subscripts.
• Use a hyphen + greater than (->) for yields.
• Click on the eye symbol to check your formatting.

1. + 20/24 points Previous Answers My Notes Write net equation for the spontaneous redox reaction and determine the standard cell potential that results when each of the following redox couples are connected in an electrochemical cell. Instructions: • Enter all substances in the order listed at the top of the column. • Use a carot to indicate a superscript, but do nothing for subscripts. Use a hyphen + greater than (->) for yields. • Click on the eye symbol to check your formatting. Couples Rxn: Ox(1) + Red(2) + other -> Red(1) + Ox(2) + other E° (V) Cu/Cu2+ and Cr3+/cr 3Cu^2+ + 2Cr -> 3Cu + 2Cr^3+ 1.08 Hg2+/Hg and Fe3+ / Fe2+ Hg^2+ + 2Fe^2+ -> Hg + 2Fe13+ .081 H1+/H2 and Ni2+/Ni 2H^1+ + Ni -> Ni^2+ + H2 .23 Cr/Cr3+ and Ti2+/Ti 2Cr3+ + 3Ti -> 2Cr + 3 Ti^2+ .89

Answer 1

Part.C :-

H⁺|H₂ and Ni²⁺|Ni

Because Standard reduction potential of Ni (s) is more negative that is - 0.26 V than H₂ (g) i.e. 0.0 V , So Ni act as reducing agent and H₂ act as oxidizing agent.

Oxidation half cell reaction is :

Ni (s) -----------------> Ni²⁺ (aq) + 2e^- , E⁰_Oxidation = +0.26 V

Reduction half cell reaction is :

2 H⁺ (aq) + 2e^------------------> H₂ (g)  , E⁰_reduction = 0.0 V

Net ionic equation of spontaneous reaction is :

2 H+ (aq) + Ni (s) ---------------> H2 (g) + Ni2+ (aq)

E⁰_cell = E⁰_Oxidation + E⁰_reduction

E⁰_cell = 0.26 V + 0.0 V

E0cell = 0.26 V