Electrochemical Cells

The cathode is ___________. 

Sn(s)|Sn(aq)²⁺‖Ag(aq)²⁺|Ag(s). 

• Sn 

• Sn²⁺ 

• Ag 

• Ag²⁺ 

The cathode is ___________. 

Zn(s)|Zn(aq)²⁺‖Cd(aq)²⁺|Cd(s). 

• Zn 

• Zn²⁺ 

• Cd 

• Cd²⁺ 

Which of the following statements is/are true? 

I. The electrons are transferred from Ag to Mg 

II. At the end of the reaction, the concentration of Ag+ decreases 

III. The mass of Mg would decrease during the course of the reaction 

Mg / Mg²⁺ // Ag⁺ / Ag 

• II and III only 

• I and II only 

• II only

• III only

2 Al (s) + 3 Zn²⁺ (aq) → 2 Al³⁺ (aq) + 3 Zn (s) 

The 𝐸_{𝑐𝑒𝑙𝑙}^𝑜 = _____________ V. 

• +0.90 

• −2.42 

• −0.90 

• +2.42 

Mg (s) + Zn²⁺ (aq) → Mg²⁺ (aq) + Zn (s) 

The 𝐸_{𝑐𝑒𝑙𝑙}^𝑜 = _____________ V. 

• +1.61 

• −3.49 

• −1.61 

• +3.49  

Which is the incorrect statement about voltaic cells?

• Oxidation occurs at the cathode (positive electrode)

• Electricity is produced as the result of spontaneous exothermic chemical reactions

• Reduction occurs at the cathode (positive electrode)

• Voltaic cells are also called galvanic cells

Which is the conventional way to depict a cell made from a zinc half-cell connected to a copper half-cell?

• Zn2+(aq) / Zn(s) || Cu(s) / Cu2+(aq)

• Zn2+(aq) / Zn(s) || Cu2+(aq) / Cu(s)

• Zn(s) / Zn2+(aq) || Cu2+(aq) / Cu(s)

• Zn(s) / Zn2+(aq) || Cu(s) / Cu2+(aq)

Which is the correct half-equation for the reaction taking place at the cathode during the operation of a cell constructed from a zinc half-cell connected to a copper half-cell?

• Zn2+(aq) + 2e− → Zn(s)

• Cu(s) → Cu2+(aq) + 2e−

• Zn(s) → Zn2+(aq) + 2e−

• Cu2+(aq) + 2e− → Cu(s) 

Magnesium is above nickel in the activity series.

What must be true about a cell made from a nickel half-cell and a magnesium half-cell when it is operating.

• The overall reaction:

  Mg(s) + Ni2+(aq) → Ni(s) + Mg2+(aq) is spontaneous

• The electrons will flow through the external circuit from nickel to magnesium

• The half-equation for the reaction taking place at the anode is:

  Ni2+(aq) + 2e− → Ni(s)

• The concentration of Ni2+ ions in the nickel half-cell will increase

Explain the function of a salt bridge in a voltaic cell

• provides an electrical connection between the two half-cells to complete the circuit

• provides an pathway for electrons to flow to each of the half-cells

• allows ions to flow into or out of the half-cells to balance out the charges in the half-cells

• prevents the flow of the anions and cations from the salt used in the salt bridge to the two half-cells