a. Write two half-equations for the reactions that take place when Fe²⁺(aq) is oxidised by dichromate(VI) ions.

b. Combine the two half-equations and write the equation for the oxidation of Fe²⁺(aq) by dichromate(VI) ions.

c. Work out the E^θvalue of the cell made when the two half-cells in part a are connected and the reaction in part b takes place. Explain what this value predicts about the likelihood of Fe²⁺(aq) being oxidised by dichromate(VI) ions.

d. How many moles of Fe²⁺(aq) can 1 mole of dichromate(VI) oxidise?

e. In a titration, 25.0 cm³ of an solution containing Fe²⁺(aq) ions was completely oxidised by 15.30 cm³ of 0.00100 mol dm^–3 potassium dichromate(VI) solution.

i. How many moles of potassium dichromate(VI) are there in 15.30 cm³ of 0.00 100 mol dm^–3 solution?

ii. How many moles of Fe²⁺ were present in the 25.0 cm³ of solution?

iii. What was the concentration of the Fe²⁺(aq) in the flask at the start of the titration?