Topic 6.2: Electron Transfer Reactions Questions

State the oxidation state of chlorine in ClO₃⁻.

State what must be balanced in a half-equation, besides the atoms.

Calculate the standard cell potential for a cell made from the Zn2+/Zn half-cell (-0.76 V) and the Ag+/Ag half-cell (+0.80 V).

Draw a labelled diagram of a voltaic cell.

For the reaction Zn + Cu²⁺ → Zn²⁺ + Cu, identify the species oxidised, the species reduced and the oxidising agent, giving oxidation states to support each.

Explain, in terms of electrons, what is meant by oxidation and by reduction, and state why the two always occur together.

Deduce whether the reaction 2FeCl₂ + Cl₂ → 2FeCl₃ is a redox reaction, justifying your answer with oxidation states.

In a voltaic cell made from zinc in zinc sulfate and copper in copper(II) sulfate, state which electrode is the negative electrode, write the half-equation occurring there, and state the direction of electron flow in the external circuit.

State two differences between a voltaic cell and an electrolytic cell.

During the electrolysis of molten sodium chloride, state the product at each electrode and write the half-equation at the cathode.

Explain the purpose of the salt bridge in a voltaic cell and state what would happen without it.

Explain what the activity series shows, and predict whether zinc will displace copper from copper(II) sulfate solution.

Describe what would be observed when a piece of magnesium is placed in copper(II) sulfate solution, and write the ionic equation.

Explain, in terms of electron transfer, why a displacement reaction between a metal and a metal ion is a redox reaction.

Predict, with a reason, whether any reaction occurs when silver is placed in dilute hydrochloric acid.

Write the two half-equations for the reaction Zn + Cu²⁺ → Zn²⁺ + Cu, labelling which is oxidation and which is reduction.

Balance the half-equation for the reduction of manganate(VII) in acidic solution: MnO₄⁻ + H⁺ + e⁻ → Mn²⁺ + H₂O

Explain why the electrons must cancel when two half-equations are combined into an overall redox equation.

Combine the half-equations Fe²⁺ → Fe³⁺ + e⁻ and Cl₂ + 2e⁻ → 2Cl⁻ into a balanced overall equation.

Deduce the oxidation state of the named element in each of: sulfur in SO₄²⁻, manganese in MnO₄⁻ and chromium in Cr₂O₇²⁻.