During an analytical redox titration used to determine the concentration of active ingredient in commercial bleach, iodine (I2\text{I}_2I2) reacts with sodium thiosulfate (Na2S2O3\text{Na}_2\text{S}_2\text{O}_3Na2S2O3) according to the following equation:
I2(aq)+2Na2S2O3(aq)→2NaI(aq)+Na2S4O6(aq) \text{I}_2(\text{aq}) + 2\text{Na}_2\text{S}_2\text{O}_3(\text{aq}) \rightarrow 2\text{NaI}(\text{aq}) + \text{Na}_2\text{S}_4\text{O}_6(\text{aq}) I2(aq)+2Na2S2O3(aq)→2NaI(aq)+Na2S4O6(aq)Which statement correctly describes the role and behavior of iodine (I2\text{I}_2I2) in this reaction?
It acts as the reducing agent because it reduces sulfur and is itself oxidised.
It acts as the reducing agent because it oxidises sulfur and is itself reduced.
It acts as the oxidising agent because it reduces sulfur and is itself oxidised.
It acts as the oxidising agent because it oxidises sulfur and is itself reduced.
55 exam-style questions on OCR GCSE Chemistry Types of chemical reactions. Each one has a worked solution and a mark scheme showing where the marks go.