Feasibility of redox reactionsEdexcel International A Level Chemistry: Mind map

Exam questions on Feasibility of redox reactions

1. Standard electrode potentials: Cl₂(g)|Cl⁻(aq) +1.36 V; Br₂(aq)|Br⁻(aq) +1.09 V; I₂(aq)|I⁻(aq) +0.54 V.
   Chlorine water is added to aqueous potassium bromide. Calculate E°cell for the reaction and state whether it is feasible.2 marks
2. Copper(I) ions in aqueous solution can undergo disproportionation. Standard electrode potentials: Cu²⁺(aq) + e⁻ ⇌ Cu⁺(aq) +0.15 V; Cu⁺(aq) + e⁻ ⇌ Cu(s) +0.52 V.
   Use the data to show that copper(I) ions disproportionate in aqueous solution under standard conditions.2 marks
3. The reaction 2Fe³⁺(aq) + 2I⁻(aq) → 2Fe²⁺(aq) + I₂(aq) is studied at 298 K. Standard electrode potentials: Fe³⁺(aq)|Fe²⁺(aq) +0.77 V; I₂(aq)|I⁻(aq) +0.54 V. Use F = 96 500 C mol⁻¹ and R = 8.31 J K⁻¹ mol⁻¹. For a cell reaction in which n electrons are transferred: ΔS_total = nFE°cell / T and ln K = nFE°cell / (RT).
   Calculate E°cell and the total entropy change for this reaction at 298 K.3 marks