Manganese(IV) oxide, MnO2, can be used in the preparation of both chlorine and oxygen. Reaction 1 MnO2(s) + 4HCl(aq) → Cl2(g) + 2H2O(l) + MnCl2(aq) Reaction 2 2H2O2(aq) → O2(g) + 2H2O(l) In reaction 2 manganese(IV) oxide acts as a catalyst.

1. (a)Reaction 1 converts chloride ions into chlorine molecules. Explain why this is an example of oxidation.[1]
2. (b)Reaction 1 is investigated using different masses of MnO2. The results are shown in the table. volume of HCl /cm³ | concentration of HCl(aq) in mol/dm³ | mass of MnO2 used /g | volume of Cl₂ formed at room temperature and pressure /dm³ 100 | 1.0 | 1.74 | 0.48 100 | 1.0 | 0.87 | 0.24 Explain the difference in the volume of chlorine formed.[2]
3. (c)Reaction 2 is investigated using different masses of MnO2. The results are shown in the table. volume of H2O2(aq) /cm³ | concentration of H2O2 in mol/dm³ | mass of MnO2 used /g | volume of O₂ formed at room temperature and pressure /dm³ 100 | 1.0 | 1.74 | 1.20 100 | 1.0 | 0.87 | Predict the volume of oxygen, measured at room temperature and pressure, when 0.87 g of MnO2 is used. Write your answer in the table.[1]
4. (d)Chlorine is bubbled through aqueous iron(II) chloride to form iron(III) chloride. Explain, with the aid of equations, how aqueous sodium hydroxide can be used to distinguish between aqueous iron(II) chloride and aqueous iron(III) chloride.[4]
5. (e)Describe the chemical test for chlorine. test ........................................................................................................................ observation .............................................................................................................[2]