Strength of Oxidising and Reducing Agent & Predict Spontaneity

What is the reducing agent of this reaction?

2Al (s) + 6H⁺ (aq) → 2Al³⁺ (aq) + 3H₂ (g)

• H⁺

• Al³⁺

• Al

• H₂

In the list of standard electrode potentials, the strongest oxidising agent is...

• K

• K⁺

• F₂

• F^-

Which statement is correct?

• Ca²⁺ can oxidize Ni
• Ni²⁺ can reduce Ca²⁺
• Fe³⁺ can oxidize Ni
• Fe³⁺ can reduce Ca²⁺

Which of the species strong oxidizing agent?

Cl₂(g) + 2e → 2Cl^-(aq) E^ocell = + 1.36 V

Cu²⁺(aq) + 2e → Cu(s) E^ocell = + 0.34 V

Ni²⁺(aq) + 2e → Ni(s) E^ocell = – 0.25 V

Ca²⁺(aq) + 2e → Ca(s) E^ocell = – 2.87 V

• Cl₂(g)

• Cu²⁺(aq)

• Ni²⁺(aq)

• Ca²⁺(aq)

Arrange the species increasing order oxidizing agent?

Cl₂(g) + 2e → 2Cl^-(aq) E^ocell = + 1.36 V

Cu²⁺(aq) + 2e → Cu(s) E^ocell = + 0.34 V

Ni²⁺(aq) + 2e → Ni(s) E^ocell = – 0.25 V

Ca²⁺(aq) + 2e → Ca(s) E^ocell = – 2.87 V

• Ca < Ni < Cu < Cl^-

• Cl^- < Cu < Ni < Ca

• Ca²⁺ < Ni²⁺ < Cu²⁺ < Cl₂

• Cl_{2 <} Cu²⁺ < Ni²⁺ < Ca²⁺

A galvanic cell was set up using the Cu²⁺/Cu and Fe³⁺/Fe half-cells. The standard redox potentials for these half-cells are: Cu²⁺(aq)  +  2e^- →   Cu(s); E⁰ = +0.34 V

Fe³⁺(aq)  +  e^- → Fe²⁺(aq); E⁰ = +0.77 V

The oxidant and reductant reacting in this galvanic cell are, respectively:   

• Fe³⁺; Cu
• Fe²⁺; Cu
• Cu²⁺; Fe³⁺
• Cu²⁺; Fe²⁺

Consider the galvanic cell reaction Zn (s) + Cu²⁺ (aq) → Cu (s) + Zn²⁺ (aq) When the cell is running spontaneously, which is the only true statement?

• The copper electrode loses mass and the zinc electrode is the cathode.

• The copper electrode gains mass and the copper electrode is the cathode.

• The zinc electrode gains mass and the zinc electrode is the anode.

• The zinc electrode loses mass and the zinc electrode is the cathode.

If an electrochemical reaction is spontaneous, what will E^o_cell be?

• positive

• negative

If the standard cell potential, E^o_cell is negative, the reaction is?

•  a success
• spontaneous
• non-spontaneous

Predict whether the following reaction occur spontaneously:

2Ag(s) + Br₂(g) ----------> 2Ag⁺(aq) + 2Br^-(aq)

Eº_Ag+/Ag = + 0.80 V Eº _Br2/_Br-= + 1.07 V

• Eº cell= + 0.27 V (non-spontaneous)

• Eº cell= + 0.27 V (spontaneous)

• Eº cell= - 0.37 V (non-spontaneous)

• Eº cell= - 0.37 V (spontaneous)