Household bleach is manufactured by reacting chlorine gas with a cold, dilute aqueous solution of sodium hydroxide.
Which of the following correctly identifies both the simplified ionic equation for this reaction and the change in oxidation state of the chlorine species that undergoes oxidation?
Ionic equation: Cl2(g)+2OH−(aq)→Cl−(aq)+ClO−(aq)+H2O(l)\text{Cl}_2(\text{g}) + 2\text{OH}^-(\text{aq}) \rightarrow \text{Cl}^-(\text{aq}) + \text{ClO}^-(\text{aq}) + \text{H}_2\text{O}(\text{l})Cl2(g)+2OH−(aq)→Cl−(aq)+ClO−(aq)+H2O(l)
Oxidation state change: 0→+10 \rightarrow +10→+1
Ionic equation: 3Cl2(g)+6OH−(aq)→5Cl−(aq)+ClO3−(aq)+3H2O(l)3\text{Cl}_2(\text{g}) + 6\text{OH}^-(\text{aq}) \rightarrow 5\text{Cl}^-(\text{aq}) + \text{ClO}_3^-(\text{aq}) + 3\text{H}_2\text{O}(\text{l})3Cl2(g)+6OH−(aq)→5Cl−(aq)+ClO3−(aq)+3H2O(l)
Oxidation state change: 0→+50 \rightarrow +50→+5
Ionic equation: Cl2(g)+2OH−(aq)→Cl−(aq)+ClO−(aq)+H2O(l)\text{Cl}_2(\text{g}) + 2\text{OH}^-(\text{aq}) \rightarrow \text{Cl}^-(\text{aq}) + \text{ClO}^-(\text{aq}) + \text{H}_2\text{O}(\text{l})Cl2(g)+2OH−(aq)→Cl−(aq)+ClO−(aq)+H2O(l)
Oxidation state change: 0→−10 \rightarrow -10→−1
Ionic equation: 3Cl2(g)+6OH−(aq)→5Cl−(aq)+ClO3−(aq)+3H2O(l)3\text{Cl}_2(\text{g}) + 6\text{OH}^-(\text{aq}) \rightarrow 5\text{Cl}^-(\text{aq}) + \text{ClO}_3^-(\text{aq}) + 3\text{H}_2\text{O}(\text{l})3Cl2(g)+6OH−(aq)→5Cl−(aq)+ClO3−(aq)+3H2O(l)
Oxidation state change: 0→+10 \rightarrow +10→+1
37 exam-style questions on AQA A Level Chemistry Group 7(17), the halogens, covering Trends in properties and Uses of chlorine and chlorate(I). Each one has a worked solution and a mark scheme showing where the marks go.