The equation represents the reaction of a halogen with aqueous bromide ions. $X_2 + 2\text{Br}^- \rightarrow 2X^- + \text{Br}_2$. Which words fill gaps 1, 2 and 3?
- A1 chlorine, 2 brown, 3 colourless
- B1 chlorine, 2 colourless, 3 brown
- C1 iodine, 2 brown, 3 colourless
- D1 iodine, 2 colourless, 3 brown