Chemistry · Oct / Nov 2022 · Paper 11 · Question 25

Thiosulfate ions, S2O3^2–, react with iodine, I2, in aqueous solution. 2S2O3^2–(aq) + I2(aq) → 2I–(aq) + S4O6^2–(aq) In this reaction, the S2O3^2– ions ......1...... electrons and are ......2...... . Which words correctly complete gaps 1 and 2?

1. Again, oxidised
2. Bgain, reduced
3. Close, oxidised
4. Dlose, reduced

As printed in the paper