A student added different known amounts of potassium nitrate to separate samples of an acidified solution containing an excess of Fe2+ ions. After reaction, the amount of Fe2+ remaining was found by titration, so the amount of Fe2+ oxidised to Fe3+ could be calculated. The nitrate ion was reduced to a single nitrogen-containing product.
Possible nitrogen-containing products:
| Product | NH4+ | N2 | N2O | NO | NO2 |
|---|---|---|---|---|---|
| Oxidation state of N | -3 | 0 | +1 | +2 | +4 |
Write a half-equation for the oxidation of Fe2+ ions.
[1]
Use the graph to determine the number of moles of Fe2+ oxidised by one mole of NO3- ions.
[1]
Use your answers to parts (a) and (b), and the table, to deduce the nitrogen-containing product. Explain your reasoning.
[2]
Write a half-equation for the reduction of NO3- ions to the product in part (c) in acidic solution.
[2]
Write an overall ionic equation for the reaction between Fe2+ ions and NO3- ions in acidic solution.
[1]