A student investigates the displacement reactions of the Group 7 elements.
They add aqueous chlorine (Cl2\text{Cl}_2Cl2) to separate test tubes containing solutions of sodium chloride (NaCl\text{NaCl}NaCl), sodium bromide (NaBr\text{NaBr}NaBr), and sodium iodide (NaI\text{NaI}NaI).
An organic solvent, cyclohexane, is then added to each test tube. The mixtures are shaken and allowed to settle into two distinct layers.
Table 1 shows the observations for the top cyclohexane layer.
Table 1
| Sodium halide solution | Colour of cyclohexane layer after adding chlorine and shaking |
|---|---|
| Sodium chloride | Pale green |
| Sodium bromide | Orange |
| Sodium iodide | Violet |
Explain the observations shown in Table 1.
Your response should include ionic equations for any reactions that occur and account for the trend in reactivity of the Group 7 elements.
106 exam-style questions on Edexcel GCSE Chemistry 7.2 Group 7, covering 7.2.1 Physical properties of the halogens, 7.2.2 Reactions of the halogens, 7.2.3 Relative reactivity and displacement reactions of the halogens, and 7.2.4 Halogen displacement as a redox reaction. Each one has a worked solution and a mark scheme showing where the marks go.