Topic 19 Electrochemistry

Which statement is correct for the overall reaction in a voltaic cell?

2AgNO₃(aq) + Ni(s) → 2Ag(s) + Ni(NO₃)₂(aq)         

E ^θ = +1.06 V

• Electrons flow from Ag electrode to Ni electrode

• Ni is oxidized to Ni²⁺ at the cathode (negative electrode).

• Ag⁺ is reduced to Ag at the anode (positive electrode).

• Ag has a more positive standard electrode potential value than Ni.

Consider tis table of standard electrode potentials. 

Which is the strongest oxidizing agent?

• Pb²⁺

• Pb

• Al³⁺

• Al

Which E^⦵ value, in V, for the reaction Mn (s) + Zn²⁺(aq) → Mn²⁺(aq) + Zn (s) can be deduced from the following equations?

Mn (s) + 2Ag⁺(aq) → Mn²⁺(aq) + 2Ag (s)     E^⦵ = 1.98 V

Zn (s) + Cu²⁺(aq) → Zn²⁺(aq) + Cu (s)        E^⦵ = 1.10 V

Cu (s) + 2Ag⁺(aq) → Cu²⁺(aq) + 2Ag (s)      E^⦵ = 0.46 V

• 0.42

• 1.34

• 2.62

• 3.54

Consider these standard electrode potentials: 

Which species will react with each other spontaneously under standard conditions?

• Zn²⁺(aq) + Pb (s)

• Pb²⁺(aq) + Br₂(l)

• Zn (s) + Br⁻(aq)

• Pb (s) + Br₂ (l)

Consider the standard electrode potentials:

Cr³⁺ (aq) + 3e⁻   Cr (s)       E^Θ = −0.74 V

Hg²⁺ (aq) + 2e⁻   Hg (l)      E^Θ = +0.85 V

What is the cell potential, in V, for the voltaic cell?

2Cr (s) + 3Hg²⁺ (aq) → 3Hg (l) + 2Cr³⁺ (aq)

• −1.59

• +0.11

• +1.07

• +1.59

Which gives the equation and cell potential of the spontaneous reaction?

• A

• B

• C

• D

What is the standard half-cell potential of copper if the “zero potential reference electrode” is changed from the standard hydrogen electrode to a standard zinc electrode?

• –1.1

• –0.34

• +0.34

• +1.1

Which is not a requirement of the standard hydrogen electrode (SHE)?

• V = 1 dm³

• p(H₂) = 100 kPa

• use of platinum as the electrode material

• [H₃O⁺] = 1 mol dm⁻³

What would be the electrode potential, E^⦵, of the Mn²⁺(aq)|Mn (s) half-cell if Fe³⁺(aq)|Fe²⁺(aq) is used as the reference standard?

Mn²⁺ (aq) + 2e⁻   Mn (s)           E^⦵ = −1.18 V

Fe³⁺ (aq) + e⁻   Fe²⁺(aq)          E^⦵ = +0.77 V

• −1.95 V

• −0.41 V

• +0.41 V

• +1.95 V

What is the order of increasing mass deposited by this electrolytic cell?

A_r  Ag = 108,  Cu = 64,  Sb = 122

• Ag < Cu < Sb

• Sb < Ag < Cu

• Cu < Ag < Sb

• Cu < Sb < Ag